free Math puzzles for 1st grade | Maths puzzles, Fun math ... - Free Printable

Let's solve this puzzle step by step.

This is a math puzzle where you need to:

1. Calculate each row and fill the result in the rightmost column.
2. Calculate each column and fill the result in the bottom row.
3. The shaded cells are intermediate sums, which will be used for both row and column calculations.

Each puzzle block is a 4x4 grid with some numbers and operations, and we'll solve them one at a time.

---

🔷 Puzzle 1 (Top Left)

```
10 + 10 = ?
+ + +
6 + 4 = ?
= = =
? + ? = ?
```

#### Step 1: Fill in the row results (right column)
- Row 1: 10 + 10 = 20
- Row 2: 6 + 4 = 10
- Row 3: We don’t have values yet, but it’s the sum of the column totals from above.

Wait — let’s look more carefully.

Actually, this is a cross-sum puzzle where:
- The first two columns contain numbers.
- The third column has "+" signs, meaning we add the two numbers above/below.
- The last column is for the row sum.
- The bottom row is for column sums.

But the structure seems like:

```
[ A ] + [ B ] = [ C ]
+ + +
[ D ] + [ E ] = [ F ]
= = =
[ G ] + [ H ] = [ I ]
```

So:
- C = A + B
- F = D + E
- I = G + H

Also:
- G = A + D
- H = B + E
- I = G + H = (A+D) + (B+E) = A+B+D+E

And:
- Bottom row: G + H = (A+D) + (B+E) = A+B+D+E
- But also, C + F = (A+B) + (D+E) → same total.

So, the bottom right cell (I) should equal sum of all four numbers.

Let’s go through each puzzle.

---

## ✔ Puzzle 1: Top Left

```
10 + 10 = ?
+ + +
6 + 4 = ?
= = =
? + ? = ?
```

Step 1: Compute row sums (right column)

- Row 1: 10 + 10 = 20
- Row 2: 6 + 4 = 10

So far:
```
10 + 10 = 20
+ + +
6 + 4 = 10
= = =
? + ? = ?
```

Step 2: Compute column sums (bottom row)

- Column 1: 10 + 6 = 16
- Column 2: 10 + 4 = 14
- So bottom row: 16 + 14 = 30

Now, check: 20 + 10 = 30 → matches.

So:
- Bottom left: 16
- Bottom middle: 14
- Bottom right: 30

Now fill in the shaded cells:
- Middle row, first column: 10 + 6 = 16
- Middle row, second column: 10 + 4 = 14
- These are already filled in the "equals" row.

Final filled table:

```
10 + 10 = 20
+ + +
6 + 4 = 10
= = =
16 + 14 = 30
```

✔ Done.

---

## ✔ Puzzle 2: Top Right

```
9 + 9 = ?
+ + +
4 + 1 = ?
= = =
? + ? = ?
```

Row sums:

- Row 1: 9 + 9 = 18
- Row 2: 4 + 1 = 5

Column sums:

- Col 1: 9 + 4 = 13
- Col 2: 9 + 1 = 10
- Total: 13 + 10 = 23

Check: 18 + 5 = 23 → good.

Fill in:

```
9 + 9 = 18
+ + +
4 + 1 = 5
= = =
13 + 10 = 23
```

✔ Done.

---

## ✔ Puzzle 3: Middle Left

```
3 + 4 = ?
+ + +
5 + 2 = ?
= = =
? + ? = ?
```

Row sums:
- 3 + 4 = 7
- 5 + 2 = 7

Column sums:
- Col 1: 3 + 5 = 8
- Col 2: 4 + 2 = 6
- Total: 8 + 6 = 14

Check: 7 + 7 = 14 → good.

Final:

```
3 + 4 = 7
+ + +
5 + 2 = 7
= = =
8 + 6 = 14
```

✔ Done.

---

## ✔ Puzzle 4: Middle Right

```
8 + 8 = ?
+ + +
9 + 1 = ?
= = =
? + ? = ?
```

Row sums:
- 8 + 8 = 16
- 9 + 1 = 10

Column sums:
- Col 1: 8 + 9 = 17
- Col 2: 8 + 1 = 9
- Total: 17 + 9 = 26

Check: 16 + 10 = 26 → good.

Final:

```
8 + 8 = 16
+ + +
9 + 1 = 10
= = =
17 + 9 = 26
```

✔ Done.

---

## ✔ Puzzle 5: Bottom Left

```
2 + 4 = ?
+ + +
9 + 2 = ?
= = =
? + ? = ?
```

Row sums:
- 2 + 4 = 6
- 9 + 2 = 11

Column sums:
- Col 1: 2 + 9 = 11
- Col 2: 4 + 2 = 6
- Total: 11 + 6 = 17

Check: 6 + 11 = 17 → good.

Final:

```
2 + 4 = 6
+ + +
9 + 2 = 11
= = =
11 + 6 = 17
```

✔ Done.

---

## ✔ Puzzle 6: Bottom Right

```
6 + 5 = ?
+ + +
3 + 9 = ?
= = =
? + ? = ?
```

Row sums:
- 6 + 5 = 11
- 3 + 9 = 12

Column sums:
- Col 1: 6 + 3 = 9
- Col 2: 5 + 9 = 14
- Total: 9 + 14 = 23

Check: 11 + 12 = 23 → good.

Final:

```
6 + 5 = 11
+ + +
3 + 9 = 12
= = =
9 + 14 = 23
```

✔ Done.

---

🟩 Final Answer Summary

Here are all six puzzles filled in:

#### 1. Top Left:
```
10 + 10 = 20
+ + +
6 + 4 = 10
= = =
16 + 14 = 30
```

#### 2. Top Right:
```
9 + 9 = 18
+ + +
4 + 1 = 5
= = =
13 + 10 = 23
```

#### 3. Middle Left:
```
3 + 4 = 7
+ + +
5 + 2 = 7
= = =
8 + 6 = 14
```

#### 4. Middle Right:
```
8 + 8 = 16
+ + +
9 + 1 = 10
= = =
17 + 9 = 26
```

#### 5. Bottom Left:
```
2 + 4 = 6
+ + +
9 + 2 = 11
= = =
11 + 6 = 17
```

#### 6. Bottom Right:
```
6 + 5 = 11
+ + +
3 + 9 = 12
= = =
9 + 14 = 23
```

---

✔ Explanation

This puzzle combines addition and logical deduction:

- Each row adds the two numbers on the left and writes the sum on the right.
- Each column adds the two numbers vertically and writes the sum in the bottom row.
- The bottom-right corner is the total sum of all four numbers in the puzzle.
- The shaded cells represent intermediate column sums (top-to-bottom), which are used to compute the final bottom row.

The key insight is that:
> Sum of row totals = Sum of column totals = Total of all four numbers

This consistency check helps verify your answers.

Let me know if you'd like this as a printable PDF or image!