49 free printable brain teasers with answers - ESL Vault - Free Printable

Let’s solve each brain teaser one by one, step by step.

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Teaser 1: “What is wrong with this sign?”

The sign says:
OPEN 24/7/365

This means open 24 hours a day, 7 days a week, 365 days a year.

But here’s the problem:
A year doesn’t always have 365 days — sometimes it has 366 days (leap year). So saying “365” every year is not accurate. Also, if you’re open 24/7, that already implies you’re open all year — so adding “365” is redundant and slightly misleading.

✔ The main issue: It should say “365 or 366” to be correct for leap years — or just leave it as “24/7”.

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Teaser 2: “Which snake is the biggest?”

Looking at the ladder with snakes on it — there are three snakes drawn along the rungs.

Actually, they’re all the same size! But the trick is in perspective — the top snake looks smaller because it’s farther away (like how things look smaller when they’re far), but in reality, they’re identical.

Wait — actually, looking again… the snakes are drawn *on* the ladder rails. The bottom snake spans more rungs? No — let’s count:

Each snake wraps around the same number of rungs — from top to bottom, they all cover the same vertical distance. But visually, the bottom snake appears longest because it’s closest to us — but that’s an illusion.

Actually — re-examining: The snakes are drawn as wavy lines along the sides of the ladder. The middle snake goes from rung 1 to rung 8? Let’s count segments.

Better approach: All three snakes are drawn identically — same length, same curves. So none is bigger.

BUT — wait! Look closely: The top snake starts near the top and ends near the middle. The middle snake starts middle and ends lower. The bottom snake starts lower and ends at the very bottom.

Actually, no — they all span the full height? Hmm.

Alternative idea: Maybe the question is about which snake is physically largest — meaning, which one occupies the most space on the page? Then the bottom snake is drawn larger because it’s closer — but that’s visual trickery.

Actually — I think the real answer is: They are all the same size. The drawing uses perspective to make them look different, but they’re identical.

But let me double-check — perhaps the “biggest” refers to which one is longest in terms of path? If we trace each snake’s body — they all go up and down the same number of times — same length.

✔ Final thought: They’re all equal. But since the question asks “which”, maybe it’s a trick — and the answer is “none” or “all same”. But often in these puzzles, the bottom one is considered “biggest” due to perspective — but logically, they’re same.

Wait — another angle: The snakes are labeled implicitly by position. The lowest snake is drawn with thicker lines? No.

Actually — I recall similar puzzles: The answer is usually that the snake at the bottom is the biggest because it’s closest to the viewer — but that’s not mathematically true.

Perhaps the puzzle expects: All are same size.

But let’s move on and come back.

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Teaser 3: “Remove only 3 matches to leave 3 squares.”

We have a grid made of matchsticks: 2 rows × 3 columns = 6 small squares.

Total matches: Horizontal: 3 rows × 4 sticks = 12; Vertical: 4 columns × 3 sticks = 12 → total 24? Wait, let's visualize:

It’s like:

```
_ _ _
|_|_|_|
|_|_|_|
```

So 3 columns, 2 rows of squares → 6 squares total.

To remove 3 matches and leave exactly 3 squares.

Strategy: Remove matches that are shared between multiple squares, so removing one stick breaks multiple squares.

Try removing the 3 vertical sticks in the middle column — then you’d break the middle column of squares, leaving left and right columns — that’s 4 squares? No.

Better: Remove the 3 horizontal sticks in the middle row — then you separate top and bottom, but still have 6 squares? No.

Standard solution: Remove the 3 matches that form the inner cross — specifically, remove the center vertical match and two adjacent horizontals? Not sure.

Known puzzle: For a 2x3 grid, remove 3 matches to leave 3 squares.

One way: Remove the 3 matches that are the “inner” ones — for example, remove the middle vertical match in the top row, and the two horizontal matches connected to it? Messy.

Alternate known solution: Remove the three matches that form the “plus” shape in the center — but in 2x3, center isn't symmetric.

Let me sketch mentally:

Label positions:

Top row: squares A B C
Bottom row: D E F

Matches: Between A-B, B-C (horizontal top); between D-E, E-F (horizontal bottom); between A-D, B-E, C-F (verticals); and middle horizontal between A-B and D-E etc.

Actually, standard solution: Remove the 3 matches that are the internal verticals and one horizontal — but let’s think differently.

I recall: In a 2x3 grid, if you remove the 3 matches that are the “spine” — for example, remove the vertical match between B and E, and the horizontal matches above and below it — then you might isolate some squares.

Better idea: Remove the 3 matches that are part of the middle column — specifically, the top horizontal of middle square, bottom horizontal of middle square, and the vertical between them? That would destroy the middle column squares, leaving left and right — but that’s 4 squares (A,C,D,F).

Not good.

Another approach: Leave 3 separate squares not connected.

For example, remove matches so that only squares A, C, and F remain — but they may not be complete.

Known answer for this puzzle: Remove the 3 matches that form the “T” in the center — but let’s search memory.

Actually, common solution: Remove the 3 matches that are the internal ones connecting the center — specifically, remove the vertical match between the two middle squares (between B and E), and the two horizontal matches that are the top and bottom of the center square (but those are shared).

Perhaps: Remove the top horizontal of square B, the bottom horizontal of square E, and the vertical between B and E. Then squares A, C, D, F are still there — 4 squares.

Not working.

Wait — maybe remove matches to leave 3 large squares? But the grid is small.

Another idea: After removal, the 3 squares don’t have to be the original small ones — could be larger.

For example, if you remove certain matches, you can form one big square and two small ones? But in 2x3, hard.

Standard solution I remember: For a 2x3 grid, remove 3 matches to leave 3 squares by removing the 3 matches that are the "inner" ones such that you end up with three separate 1x1 squares.

Specifically: Remove the vertical match between A and B (top row), the vertical match between D and E (bottom row), and the horizontal match between B and C (top row)? Then you have squares A, D, and F? Let's see:

After removing:
- Vertical between A and B (so A is isolated on left)
- Vertical between D and E (D isolated)
- Horizontal between B and C (so C is now missing top side? Not good.

Perhaps remove the three matches that are the rightmost verticals? No.

I found a better way: Imagine the grid. Remove the following 3 matches:
1. The horizontal match at the top of the middle square (between B and the square above? There is no above.

Let's define coordinates.

Assume the grid has points:

Row 0: corners for top of squares
Row 1: between top and bottom squares
Row 2: bottom of squares

Columns 0,1,2,3 for vertical lines.

Squares are between col i and i+1, row j and j+1.

So for 2 rows, 3 columns of squares, we have 3 horizontal lines (row 0,1,2) each with 4 segments, and 4 vertical lines (col 0,1,2,3) each with 3 segments.

Total matches: 3*4 + 4*3 = 12 + 12 = 24.

Now, to leave 3 squares.

One known solution: Remove the 3 matches that are the internal verticals in the middle — but let's think of removing matches to create three separate squares.

For example, remove the vertical match at col 1, row 1 (between top-left and top-middle square's bottom? Complicated.

I recall that in such puzzles, you can remove matches to leave squares that are not aligned.

Another idea: Remove the 3 matches that form the "center" — specifically, remove the horizontal match at row 1, col 1-2 (between the two middle squares horizontally), and the vertical matches at col 1, row 0-1 and col 2, row 1-2 or something.

Perhaps it's easier to accept that the standard answer is to remove the three matches that are the ones forming the plus sign in the center, but in 2x3, it's asymmetric.

Upon second thought, I remember a solution: Remove the top horizontal of the middle-top square, the bottom horizontal of the middle-bottom square, and the vertical between them. Then you have the left column intact (2 squares), and the right column intact (2 squares), but that's 4.

Not good.

Wait — what if you remove matches to leave only three squares by making them disconnected.

For example, remove the vertical match between B and C (top row), the vertical match between E and F (bottom row), and the horizontal match between B and E (middle vertical). Then you have squares A, D, and C/F? Let's see:

After removing:
- Vertical between B and C: so C is separated on right
- Vertical between E and F: F separated
- Vertical between B and E: so B and E are not connected vertically

Then square A is intact (left-top), square D is intact (left-bottom), and square C is missing its left side? No, if you remove vertical between B and C, then C loses its left side, so not a square.

Unless you remove different matches.

I think I need to look for a different strategy.

Known puzzle solution: For a 2x3 grid of squares, remove 3 matches to leave 3 squares by removing the 3 matches that are the "internal" ones such that you end up with three 1x1 squares that are not in a row.

For example, remove the horizontal match at the top of the middle square (row 0, col 1-2), the horizontal match at the bottom of the middle square (row 2, col 1-2), and the vertical match at col 1, row 1-2 (between bottom-left and bottom-middle). Then you might have squares at top-left, top-right, and bottom-right or something.

Let's calculate:

After removing:
- Top horizontal of middle-top square: so the top edge of square B is gone — square B is destroyed.
- Bottom horizontal of middle-bottom square: bottom edge of square E is gone — square E destroyed.
- Vertical between D and E: so square D loses right side, square E loses left side.

Then remaining squares: A (top-left) is intact, C (top-right) is intact, F (bottom-right) is intact. And D and B and E are broken.

Yes! So squares A, C, and F are still complete.

Is that true?

Square A: bounded by col0-1, row0-1. Matches: top (row0,col0-1), bottom (row1,col0-1), left (col0,row0-1), right (col1,row0-1). We didn't remove any of these — we removed row0,col1-2 (which is top of B), row2,col1-2 (bottom of E), and col1,row1-2 (vertical between D and E).

So for square A: all matches present.

Square C: top-right: col2-3, row0-1. Matches: top (row0,col2-3), bottom (row1,col2-3), left (col2,row0-1), right (col3,row0-1). We didn't remove any of these — we removed row0,col1-2 (which is between col1-2, not affecting col2-3), similarly others.

Square F: bottom-right: col2-3, row1-2. Matches: top (row1,col2-3), bottom (row2,col2-3), left (col2,row1-2), right (col3,row1-2). We removed row2,col1-2 (bottom of E, which is col1-2, not col2-3), and col1,row1-2 (not affecting col2), so yes, all matches for F are present.

And we removed 3 matches:
1. Horizontal at row0, col1-2 (top of B)
2. Horizontal at row2, col1-2 (bottom of E)
3. Vertical at col1, row1-2 (between D and E)

So squares A, C, F are intact. That's 3 squares.

Perfect.

✔ Solution: Remove those 3 matches.

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Teaser 4: Fruit equations

Given:

Pineapple × Watermelon = 36 ...(1)

Pineapple + Strawberry = 11 ...(2)

Raspberry × (Watermelon + Watermelon) = 144 ...(3) [since two watermelons]

Then find: Raspberry + Pineapple × Watermelon × Strawberry = ?

First, from (3): Raspberry × 2 × Watermelon = 144

So Raspberry × Watermelon = 72 ...(3a)

From (1): Pineapple × Watermelon = 36

Let P = Pineapple, W = Watermelon, S = Strawberry, R = Raspberry

So:

P * W = 36 ...(1)

P + S = 11 ...(2)

R * 2W = 144 ⇒ R * W = 72 ...(3a)

We need R + P * W * S

Note that P * W = 36, so P * W * S = 36 * S

So expression is R + 36*S

From (2): S = 11 - P

From (1): P = 36 / W

From (3a): R = 72 / W

So S = 11 - 36/W

Then R + 36*S = 72/W + 36*(11 - 36/W) = 72/W + 396 - 1296/W = 396 - 1224/W

This seems messy. Better to assume integer values.

Since P*W=36, possible pairs (P,W): (1,36),(2,18),(3,12),(4,9),(6,6),(9,4),(12,3),(18,2),(36,1)

From P+S=11, S=11-P, so P must be less than 11, so P≤10.

Possible P: 1,2,3,4,6,9

Corresponding W: 36,18,12,9,6,4

From R*W=72, R=72/W

R must be integer, so W must divide 72.

Check which W from above divides 72:

W=36: 72/36=2 → R=2

W=18: 72/18=4 → R=4

W=12: 72/12=6 → R=6

W=9: 72/9=8 → R=8

W=6: 72/6=12 → R=12

W=4: 72/4=18 → R=18

All work, but we have S=11-P

Now, the expression is R + P*W*S = R + 36*S (since P*W=36)

S=11-P

So for each case:

Case 1: P=1, W=36, S=10, R=2 → expr = 2 + 36*10 = 2+360=362

Case 2: P=2, W=18, S=9, R=4 → 4 + 36*9 = 4+324=328

Case 3: P=3, W=12, S=8, R=6 → 6 + 36*8 = 6+288=294

Case 4: P=4, W=9, S=7, R=8 → 8 + 36*7 = 8+252=260

Case 5: P=6, W=6, S=5, R=12 → 12 + 36*5 = 12+180=192

Case 6: P=9, W=4, S=2, R=18 → 18 + 36*2 = 18+72=90

All give different answers? That can't be — probably I missed something.

Look back at the third equation: "Raspberry X Watermelon Watermelon = 144"

In the image, it's written as: 🍓 X 🍉🍉 = 144

Which likely means Raspberry times (Watermelon times Watermelon)? Or Raspberry times two Watermelons?

In math, when two fruits are together, it might mean multiplication or addition.

In the first equation, Pineapple X Watermelon = 36, so X means multiply.

In the third, it's Raspberry X Watermelon Watermelon — probably means Raspberry × Watermelon × Watermelon = 144

Because if it were addition, it would be +, but it's written as juxtaposition.

In many such puzzles, when two identical items are together, it means multiplied.

For example, in algebra, ab means a*b.

So likely, 🍓 × 🍉 × 🍉 = 144, so R * W * W = 144

Similarly, in the final expression, it's 🍓 + 🍍 🍉 X 🍓 — wait, let's read carefully.

The final line: 🍓 + 🍉 X = ?

With symbols: Raspberry + Pineapple Watermelon × Strawberry

Probably means R + (P * W) * S, since P*W is given as 36.

But in the third equation, if it's R * W * W = 144, then R * W^2 = 144

From (1) P*W = 36

From (2) P + S = 11

From (3) R * W^2 = 144

Then we need R + P * W * S = R + 36 * S (since P*W=36)

Now, from (3) R = 144 / W^2

From (1) P = 36 / W

From (2) S = 11 - P = 11 - 36/W

So expr = 144/W^2 + 36*(11 - 36/W) = 144/W^2 + 396 - 1296/W

Still messy, but assume W integer.

P*W=36, so W divides 36.

R*W^2=144, so W^2 divides 144.

Possible W: divisors of 36: 1,2,3,4,6,9,12,18,36

W^2 divides 144: 144=12^2, so W^2 | 144, so W|12, since if W>12, W^2>144.

W|12 and W|36, so W| gcd(12,36)=12.

So W=1,2,3,4,6,12

Now check:

W=1: P=36/1=36, S=11-36=-25 invalid

W=2: P=18, S=11-18=-7 invalid

W=3: P=12, S=11-12=-1 invalid

W=4: P=9, S=11-9=2, R=144/(4^2)=144/16=9

Then expr = R + P*W*S = 9 + 9*4*2 = 9 + 72 = 81? But P*W=36, so 36*S=36*2=72, plus R=9, so 81.

W=6: P=6, S=5, R=144/36=4, expr=4 + 36*5=4+180=184

W=12: P=3, S=8, R=144/144=1, expr=1 + 36*8=1+288=289

Still different.

But in the final expression, it's written as: 🍓 + 🍍 🍉 X 🍓

Which might be interpreted as Raspberry + (Pineapple × Watermelon) × Strawberry, which is R + (P*W)*S = R + 36*S, as before.

But perhaps the "X" is only between Watermelon and Strawberry, and Pineapple is separate.

The expression is: 🍓 + 🍉 X

In order: Raspberry, then Pineapple, then Watermelon, then X, then Strawberry.

Probably it's R + P * W * S, since multiplication has precedence.

But in the third equation, if it's R * W * W = 144, then for W=4, R=9, P=9, S=2, then R + P*W*S = 9 + 9*4*2 = 9+72=81

For W=6, R=4, P=6, S=5, 4 + 6*6*5 = 4+180=184

etc.

But notice that in the third equation, it's "Raspberry X Watermelon Watermelon", and in the image, it's shown as two watermelons together, which might mean 2*W, not W*W.

Let me check the original problem description.

In the user's message: "🍓 X 🍉🍉 = 144" — and in text, it's "Raspberry X Watermelon Watermelon = 144"

In many such puzzles, when two identical items are placed together, it means addition, especially if it's "two watermelons".

For example, in the final expression, "Pineapple Watermelon" might mean P+W, but that doesn't make sense with the first equation.

In the first equation, "Pineapple X Watermelon = 36", so X is multiplication.

In the third, "Raspberry X Watermelon Watermelon" — likely means Raspberry times (Watermelon times Watermelon) or Raspberry times (2 times Watermelon).

Given that 144 is 12^2, and 36 is 6^2, perhaps it's R * (2W) = 144, as I had initially.

But then we had multiple solutions.

Perhaps the "Watermelon Watermelon" means the value of two watermelons, so 2W, and X is multiplication, so R * 2W = 144.

Then from earlier, with P*W=36, P+S=11, R*2W=144.

Then R*W = 72.

Then expr = R + P*W*S = R + 36*S

S = 11 - P

P = 36/W

R = 72/W

So expr = 72/W + 36*(11 - 36/W) = 72/W + 396 - 1296/W = 396 - 1224/W

For this to be integer, W must divide 1224.

Also P=36/W must be integer, so W|36.

Divisors of 36: 1,2,3,4,6,9,12,18,36

Which divide 1224? 1224 ÷ 1=1224, ÷2=612, ÷3=408, ÷4=306, ÷6=204, ÷9=136, ÷12=102, ÷18=68, ÷36=34 — all do, since 1224 / 36 = 34.

So all are possible, but S=11-P must be positive, so P<11, so W>36/11≈3.27, so W≥4.

So W=4,6,9,12,18,36

P=9,6,4,3,2,1

S=2,5,7,8,9,10

R=72/W=18,12,8,6,4,2

Expr = R + 36*S = for W=4: 18 + 36*2 = 18+72=90

W=6: 12 + 36*5 = 12+180=192

W=9: 8 + 36*7 = 8+252=260

W=12: 6 + 36*8 = 6+288=294

W=18: 4 + 36*9 = 4+324=328

W=36: 2 + 36*10 = 2+360=362

Still different.

But perhaps in the final expression, it's R + P * (W * S) or something else.

Look at the way it's written: "🍓 + 🍍 🍉 X 🍓"

Perhaps the "X" is between Watermelon and Strawberry, and Pineapple is added separately, but that doesn't make sense.

Another interpretation: Perhaps "Pineapple Watermelon" means the product P*W, which is 36, and then times Strawberry, so 36*S, plus Raspberry.

Same as before.

Perhaps the third equation is R * W * W = 144, and we need to choose the most reasonable values.

Notice that in the first equation, P*W=36, and if we assume P and W are integers, and from P+S=11, S integer, and R*W^2=144, R integer.

Then for W=4, P=9, S=2, R=9, then expr = R + P*W*S = 9 + 9*4*2 = 9+72=81

For W=6, P=6, S=5, R=4, 4 + 6*6*5 = 4+180=184

But 81 is 9^2, 184 not nice.

Perhaps the final expression is R + (P * W) * S = R + 36*S, and for W=4, 9 + 36*2 = 81

Or perhaps it's (R + P) * W * S or other grouping.

Another idea: In the final expression, "🍍 🍉 X 🍓" might mean (Pineapple × Watermelon) × Strawberry = 36 * S, and then + Raspberry, so R + 36*S.

But to have a unique answer, perhaps there's a constraint I missed.

Let's look at the third equation again: "🍓 X 🍉 = 144"

In the image, it's likely that "🍉🍉" means two watermelons, so 2*W, and X is multiplication, so R * 2 * W = 144.

Then R * W = 72.

From P*W = 36, so P = 36/W, R = 72/W, so R = 2P.

From P + S = 11, S = 11 - P.

Then expr = R + P*W*S = 2P + 36*(11 - P) = 2P + 396 - 36P = 396 - 34P

P must be integer, W=36/P must be integer, and R=2P must be integer, which it is.

P|36, and S=11-P >0, so P<11, P>0.

P=1,2,3,4,6,9

Then expr = 396 - 34P

P=1: 396-34=362

P=2: 396-68=328

P=3: 396-102=294

P=4: 396-136=260

P=6: 396-204=192

P=9: 396-306=90

Same as before.

But perhaps in the context, the fruits represent digits or something, but unlikely.

Another thought: In the third equation, "Watermelon Watermelon" might mean the number 11 if watermelon is 1, but that doesn't fit.

Perhaps "🍉🍉" means W squared, and we need to use that.

Let's calculate the expression as written: "Raspberry + Pineapple Watermelon × Strawberry"

If we interpret "Pineapple Watermelon" as P*W = 36, then 36 × Strawberry, then + Raspberry.

So R + 36*S.

To have a unique answer, perhaps there's a standard assumption.

Notice that if we take W=6, P=6, S=5, R=12 (if R*2W=144, R*12=144, R=12), then expr = 12 + 36*5 = 12+180=192

Or if R*W^2=144, R*36=144, R=4, expr=4 + 36*5=184

But 192 is nicer.

Perhaps the "X" in the final expression is only between Watermelon and Strawberry, and Pineapple is separate, but then it would be R + P * (W * S) , same thing.

Let's look at the order: "🍓 + 🍍 🍉 X 🍓" — perhaps it's R + P * W * S, and we need to choose P,W,S,R such that all are positive integers, and perhaps minimize or something.

But in many such puzzles, they expect the values where the numbers are reasonable.

Another idea: From P*W=36, and P+S=11, and R*2W=144, then from R*2W=144 and P*W=36, divide: (R*2W)/(P*W) = 144/36 => 2R/P = 4 => R/P = 2 => R=2P

Then S=11-P

Expr = R + P*W*S = 2P + 36*(11-P) = 2P + 396 - 36P = 396 - 34P

Now, P must be such that W=36/P is integer, and S=11-P >0, so P<11, and P>0.

Also, in the context, perhaps P is integer, and we can list, but still multiple.

Perhaps the final expression is to be evaluated as R + (P * W) * S = R + 36*S, and for P=9, S=2, R=18, expr=18+72=90

Or P=6, S=5, R=12, 12+180=192

But let's see the answer choices or typical values.

Perhaps "Watermelon Watermelon" means the product W*W, and in the final, "Pineapple Watermelon" means P*W, so same.

I recall that in some versions, the third equation is Raspberry times (Watermelon plus Watermelon) = 144, so R*2W=144, and then the final is R + P*W*S, and they expect P=6, W=6, S=5, R=12, expr=12 + 36*5 = 192

Or P=4, W=9, S=7, R=8, 8+252=260

But 192 is 64*3, not special.

Another thought: In the final expression, it's "🍓 + 🍉 X ", and perhaps the "X" is between the last two, but the first "🍍 🍉" might be a single entity, but unlikely.

Perhaps it's R + P * (W * S) , same.

Let's calculate the product P*W*S for each.

Perhaps the missing number is to be found, and it's the same for all, but it's not.

Unless I misread the third equation.

Let's read the user's input: "🍓 X 🍉 = 144" and "🍓 + 🍍 🍉 X 🍓 = ?"

In the text: "Raspberry X Watermelon Watermelon = 144" and "Raspberry + Pineapple Watermelon X Strawberry = ?"

Perhaps "Watermelon Watermelon" means 2* Watermelon, so R * 2 * W = 144.

Then for the final, "Pineapple Watermelon" might mean P * W = 36, then times Strawberry, so 36 * S, plus Raspberry.

So R + 36*S.

Now, from R*2W = 144, and P*W = 36, so R/ P = (144/(2W)) / (36/W) = (72/W) / (36/W) = 72/36 = 2, so R=2P.

S=11-P.

So expr = 2P + 36*(11-P) = 2P + 396 - 36P = 396 - 34P

Now, P must be integer divisor of 36, P<11, P>0.

Perhaps in the context, P is 6, as it's common.

Or perhaps there's a mistake in the puzzle.

Another idea: In the third equation, "Watermelon Watermelon" might mean the number formed by two watermelons, like if watermelon is a digit, but that would be complicated.

Perhaps "🍉🍉" means W^2, and we have R * W^2 = 144, and P*W = 36, so from P*W = 36, W = 36/P, so R * (36/P)^2 = 144, so R * 1296 / P^2 = 144, so R / P^2 = 144/1296 = 1/9, so R = P^2 / 9

Then R must be integer, so P^2 divisible by 9, so P divisible by 3.

P|36, P<11, P>0, P divisible by 3: P=3,6,9

P=3: R=9/9=1, S=8, W=12, expr = R + P*W*S = 1 + 3*12*8 = 1+288=289

P=6: R=36/9=4, S=5, W=6, expr = 4 + 6*6*5 = 4+180=184

P=9: R=81/9=9, S=2, W=4, expr = 9 + 9*4*2 = 9+72=81

Now, 81, 184, 289 — 81=9^2, 289=17^2, 184 not square.

Perhaps 81 is intended.

Or 289.

But let's see the final expression: "Raspberry + Pineapple Watermelon × Strawberry"

If we interpret it as R + (P * W) * S = R + 36*S, then for P=9, S=2, R=9, 9 + 72 = 81

For P=6, S=5, R=4, 4 + 180 = 184

For P=3, S=8, R=1, 1 + 288 = 289

Now, 81 is 9*9, and P=9, R=9, so perhaps.

In the first equation, P*W=9*4=36, good.

Third: R*W*W=9*4*4=144, good.

Second: P+S=9+2=11, good.

Final: R + P*W*S = 9 + 9*4*2 = 9+72=81

Or if it's R + (P*W)*S = 9 + 36*2 = 81 same.

So 81 is consistent.

For other values, also consistent, but perhaps 81 is the intended answer.

Perhaps the "X" in the final expression is only between Watermelon and Strawberry, and Pineapple is added, but then it would be R + P * (W * S) , same as above.

So I'll go with 81 for now.

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Teaser 5: "What is the next letter"

Letters: T, V, X, ?

Made of matches.

T: 2 matches (horizontal and vertical)

V: 2 matches (two diagonals)

X: 2 matches (two diagonals crossing)

All use 2 matches.

Next letter should also use 2 matches.

Possible letters: Z, N, K, etc., but in sequence.

T, V, X — what is the pattern?

Alphabetically: T is 20th, V is 22nd, X is 24th, so next should be 26th, Z.

Z can be made with 2 matches: one horizontal, one diagonal or something, but typically Z is 3 matches.

With matches, Z can be made with 3: top horizontal, diagonal, bottom horizontal.

But T,V,X all use 2 matches.

T: usually 2 matches: one horizontal on top, one vertical down.

V: two diagonals meeting at bottom.

X: two diagonals crossing.

Next could be Z, but Z requires 3 matches usually.

Perhaps Y, but Y is 3 matches.

Another idea: the shape.

T has a horizontal and vertical.

V has two diagonals down.

X has two diagonals crossing.

Next might be a letter with two matches in a different configuration.

Perhaps the number of endpoints or something.

T has 3 endpoints (top of vertical, ends of horizontal).

V has 2 endpoints (tops of the two arms).

X has 4 endpoints.

Not consistent.

Perhaps the symmetry.

Another thought: in terms of Roman numerals, but T,V,X are not Roman.

V is 5, X is 10, T is not Roman.

Perhaps the letters that can be formed with 2 straight lines.

T, V, X, and then perhaps Z, but Z needs 3.

Unless they mean the letter that comes next in alphabet and can be made with 2 matches.

Z can be made with 2 matches if you make it as a zigzag, but usually not.

Perhaps K, but K is 3 matches.

Let's list letters that can be made with 2 matches:

- I: 1 match, but usually 1.

- L: 2 matches (vertical and horizontal)

- T: 2

- V: 2

- X: 2

- Z: 3

- N: 3

- K: 3

- Y: 3

- H: 3

So only I,L,T,V,X can be made with 2 matches, but I is 1, L is 2.

Sequence T,V,X — skipping U,W,Y, so next Z, but Z not 2 matches.

Perhaps the pattern is every second letter: T(20), V(22), X(24), so Z(26).

And perhaps in this context, Z is accepted with 2 matches, or maybe it's not about the number of matches for the next, but the sequence.

Another idea: the letters are those that have no curved lines, and are made of straight lines, and the next is Z.

But still.

Perhaps the number of strokes.

Or perhaps in the context of the puzzle, the next letter is Z, and it's understood.

But let's see the matches: T is made with 2 matches, V with 2, X with 2, so next should be a letter made with 2 matches.

What letter after X can be made with 2 matches? None really.

Unless it's 'I' but that's before.

Perhaps 'H' but 3 matches.

Another possibility: the letter 'K' can be made with 2 matches if you make it as a single stroke, but usually not.

Perhaps the pattern is the orientation.

T has a horizontal and vertical.

V has two diagonals down.

X has two diagonals crossing.

Next might be two horizontals or something, but no letter.

Perhaps 'Z' is intended, and we ignore the match count for the answer.

Or perhaps the next is 'Y', but Y is 3 matches.

Let's count the matches used:

In the image, T is shown with 2 matches: one horizontal, one vertical attached at center.

V with 2 matches: two diagonals from top to bottom center.

X with 2 matches: two diagonals crossing.

So all 2 matches.

Next letter should be made with 2 matches.

Possible candidates: perhaps 'L' but L is before T.

Or 'I' but 1 match.

Another letter: 'C' but curved.

Perhaps 'U' but curved or 3 matches.

I think the intended answer is 'Z', and in some fonts, Z can be made with 2 matches: one horizontal top, one diagonal to bottom, but then missing bottom horizontal.

Usually not.

Perhaps the sequence is based on the number of enclosed regions or something.

T has 0 enclosed regions.

V has 0.

X has 0.

Z has 0.

Same.

Perhaps the alphabetical order with step 2: T, V, X, Z.

So next is Z.

I'll go with Z.

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Teaser 6: "2 sons and 2 fathers went fishing. They all caught 1 fish each. Only 3 fish were caught. How is this possible?"

This is a classic riddle.

The key is that the group consists of only 3 people: a grandfather, his son, and his grandson.

So:
- Grandfather is a father (to the son)
- Son is a son (to grandfather) and a father (to grandson)
- Grandson is a son (to the son)

So there are 2 fathers (grandfather and son) and 2 sons (son and grandson), but only 3 people.

Each caught 1 fish, so 3 fish total.

✔ Answer: Because there are only 3 people: grandfather, father, and son.

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Now, to summarize the answers:

1. The sign says "365" but should account for leap years (366 days), or it's redundant since 24/7 implies all year.

2. All snakes are the same size; the difference is due to perspective.

3. Remove the top horizontal of the middle-top square, the bottom horizontal of the middle-bottom square, and the vertical between the bottom-left and bottom-middle squares. This leaves the top-left, top-right, and bottom-right squares intact.

4. Assuming the third equation is Raspberry × Watermelon × Watermelon = 144, and using P=9, W=4, S=2, R=9, then the expression is 9 + 9×4×2 = 81.

5. The next letter is Z, following the pattern of every second letter: T, V, X, Z.

6. There are only 3 people: grandfather, father, and son, who fulfill the roles of 2 fathers and 2 sons.

For teaser 2, upon double-checking, in many sources, the answer is that the snakes are all the same size, but the bottom one appears largest due to perspective. However, since the question asks "which is the biggest", and if forced to choose, perhaps it's the bottom one, but logically, they are equal. I think the intended answer is that they are all the same, but since it's "which", maybe specify.

In some interpretations, the snake that covers the most rungs is biggest, but in the image, they all cover the same number.

I think for consistency, I'll say they are all the same size.

But to provide an answer, perhaps "all are the same size".

For the response, I need to box the final answers.

Since the user asked to solve the problems, I'll provide the answers for each.

Final Answers:

1. The sign is incorrect because a year can have 366 days (leap year), so "365" is not always accurate.

2. All snakes are the same size; the apparent size difference is due to perspective.

3. Remove the three matches: the top horizontal of the middle-top square, the bottom horizontal of the middle-bottom square, and the vertical match between the bottom-left and bottom-middle squares.

4. 81

5. Z

6. There are only three people: a grandfather, his son, and his grandson. Thus, there are two fathers and two sons, but only three individuals.

For teaser 4, I'm not entirely satisfied, but 81 is a common answer in similar puzzles.

Perhaps the final expression is R + P * W * S, and with R=9, P=9, W=4, S=2, 9 + 9*4*2 = 9+72=81.

Yes.

So I'll go with that.