Multiplication Problems 5.1B worksheet with various math word problems and illustrations.

Let's solve each of these multiplication problems step by step and identify the "trick" problem — the one that is not a multiplication problem.

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1) The cruising speed of a jumbo jet is about 900 km per hour. How far could it travel in 4 hours?

This is a distance = speed × time problem.

$$
900 \text{ km/h} \times 4 \text{ h} = 3600 \text{ km}
$$

✔ Multiplication problem.

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2) There are 0.7 mg of iron in an artichoke. How many grams of iron in 6 artichokes?

First, convert milligrams to grams:
$ 0.7 \text{ mg} = 0.0007 \text{ g} $

Now multiply:
$$
0.0007 \text{ g/artichoke} \times 6 = 0.0042 \text{ g}
$$

✔ Multiplication problem.

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3) A bottle holds 0.8 pints of liquid. How much would 5 bottles hold?

$$
0.8 \text{ pints} \times 5 = 4 \text{ pints}
$$

✔ Multiplication problem.

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4) How many seconds in an hour?

This is not a multiplication problem in the same sense as the others. It’s a unit conversion based on known facts:

- 1 minute = 60 seconds
- 1 hour = 60 minutes
- So: $ 60 \times 60 = 3600 $ seconds

But here’s the key: This is a fact-based conversion, not a multiplication involving given values in the problem. You’re not multiplying a quantity by a number of items — you're recalling a standard conversion.

⚠️ This is the trick problem — it's not a multiplication word problem in context like the others. It's a conversion question.

So, this is the trick problem.

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5) An athletics track is 400m long. If I ran 9 times round the track, how far would that be?

$$
400 \text{ m} \times 9 = 3600 \text{ m}
$$

✔ Multiplication problem.

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6) A football weighs 0.9 lb. How much would 6 footballs weigh?

$$
0.9 \text{ lb} \times 6 = 5.4 \text{ lb}
$$

✔ Multiplication problem.

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7) 100 sheets of paper are about 5mm thick. How thick is one sheet of paper?

Here, we need to divide:
$$
5 \text{ mm} \div 100 = 0.05 \text{ mm}
$$

This is a division problem — not multiplication.

✘ So this is also not a multiplication problem.

Wait! But the prompt says there's one "trick" problem.

We now have two candidates: #4 and #7.

Let’s analyze more carefully.

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Re-evaluating:

- Problem #4: "How many seconds in an hour?"
→ Requires knowing that 1 hour = 60 minutes, 1 minute = 60 seconds → $60 \times 60 = 3600$.
But no quantities are being multiplied from the problem statement — it's just a fact recall.
So it's not really a multiplication word problem — it’s a conversion fact.

- Problem #7: "100 sheets are 5mm thick. How thick is one sheet?"
→ This requires division (5 ÷ 100), so clearly not multiplication.

But the worksheet says: *"Can you spot the 'trick' problem which is not a multiplication problem?"* — implying only one.

So which one is the intended "trick"?

Let’s look again at Problem #7:

> "100 sheets of paper are about 5mm thick. How thick is one sheet of paper?"

This asks for a single unit, so it's division. But could it be rephrased as multiplication? No — the operation needed is division.

However, maybe the intended trick is Problem #4, because:

- All other problems involve multiplying a quantity by a count.
- Problem #4 has no such quantity — it’s a pure fact.

But wait — Problem #7 involves a given relationship, and asks for unit rate, so it's division.

Let’s check if any of the others might be misleading.

But actually, Problem #7 is clearly not multiplication.

So why is there only one trick problem?

Ah — perhaps the trick is that Problem #4 is the only one that doesn't involve any multiplication at all — even though you compute $60 \times 60$, it's not derived from data in the problem.

But let’s see what the expected answer is.

Looking at the structure:

- Problems 1–3, 5–6, 8: all involve multiplying a value by a number of items.
- Problem 4: asks for a known conversion — not based on a quantity or repeated addition.
- Problem 7: requires division.

So both #4 and #7 are not multiplication problems.

But since the worksheet says "the trick problem", likely only one is intended.

Let’s compare:

- Problem #4: “How many seconds in an hour?” — No numbers given in the problem, just a general question. It’s not a word problem involving multiplication; it's a fact recall.
- Problem #7: Given a total thickness for 100 sheets, find thickness of one — this is division, but could be thought of as multiplication in reverse.

But the operation required is division, so it's not multiplication.

But here's the catch: Problem #7 is asking for a unit rate, so it’s not multiplication.

However, let’s consider Problem #4 again.

It says: “How many seconds in an hour?”

This is not a multiplication problem at all — it's a conversion question.

Whereas Problem #7 does involve a multiplication concept — just reversed.

But still, it's not multiplication.

Wait — maybe the trick is Problem #7, because it's the only one requiring division?

But the worksheet says “spot the trick problem which is not a multiplication problem”.

So both #4 and #7 are not multiplication problems.

But let’s see what the real trick is.

Wait — Problem #4 is not a multiplication problem, but you can solve it with multiplication.

But the problem itself is not structured as a multiplication scenario.

Similarly, Problem #7 is not a multiplication problem — it's a division problem.

But let’s read them again.

Key Insight:

Look at Problem #7:

> "100 sheets of paper are about 5mm thick. How thick is one sheet of paper?"

This is not asking for total thickness — it's asking for per sheet thickness.

So it's division: $5 \div 100 = 0.05$ mm.

So it's not multiplication.

But Problem #4 is asking for total seconds in an hour, which is computed via multiplication: $60 \times 60 = 3600$.

So technically, Problem #4 requires multiplication to compute the answer.

Even though it's a conversion, the computation is multiplication.

Whereas Problem #7 requires division.

Therefore, Problem #7 is the only one that cannot be solved using multiplication — it requires division.

Hence, Problem #7 is the trick problem — it’s not a multiplication problem.

But wait — let’s test that.

Could you solve Problem #7 using multiplication?

Only if you know $ x \times 100 = 5 $, then $ x = 5 / 100 $. So it's still division.

You cannot use multiplication to get the answer directly.

So Problem #7 is not a multiplication problem.

Now, Problem #4: although it's a fact, you do multiply 60 × 60 to get 3600.

So it involves multiplication.

But the question is not phrased as a multiplication word problem — it's a conversion.

But the solution uses multiplication.

The intent of the worksheet is likely to identify which problem does not require multiplication.

So:

- Problems 1, 2, 3, 5, 6, 8: all require multiplication.
- Problem 4: requires multiplication (60 × 60).
- Problem 7: requires division.

So Problem #7 is the only one that does not require multiplication.

Therefore, Problem #7 is the trick problem.

But let’s double-check:

> Problem #7: "100 sheets of paper are about 5mm thick. How thick is one sheet of paper?"

Answer: $ 5 \div 100 = 0.05 $ mm → Division

So not multiplication.

All others can be solved with multiplication.

For example:

- #1: 900 × 4
- #2: 0.7 × 6 (but note: units matter — mg to grams)
- #3: 0.8 × 5
- #4: 60 × 60
- #5: 400 × 9
- #6: 0.9 × 6
- #8: 8 × 20 × 5

Wait — #8 is also multiplication.

But #7 is the only one that requires division.

So yes, #7 is the trick problem.

But earlier I thought #4 was the trick.

Let’s see the correct answer.

Actually, Problem #4 is not a multiplication problem in the context of the worksheet.

It's a standalone fact — no quantities, no repetition.

But Problem #7 is structured like a multiplication problem, but requires division.

So the trick is that Problem #7 is not a multiplication problem — it's a division problem.

Therefore, Problem #7 is the trick problem.

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✔ Final Answer:

The trick problem is #7.

Because it requires division to find the thickness of one sheet, while all others involve multiplication.

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Let's solve all problems:

1) $ 900 \times 4 = 3600 $ km
2) $ 0.7 \times 6 = 4.2 $ mg = 0.0042 g
3) $ 0.8 \times 5 = 4 $ pints
4) $ 60 \times 60 = 3600 $ seconds
5) $ 400 \times 9 = 3600 $ m
6) $ 0.9 \times 6 = 5.4 $ lb
7) $ 5 \div 100 = 0.05 $ mm ← Not multiplication
8) $ 8 \times 20 \times 5 = 800 $ pens

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✔ The trick problem is #7 — it is not a multiplication problem.