Multiplication Problems 5.1B worksheet featuring various word problems and a "trick" problem to identify.

Let's solve each of these multiplication problems step by step and identify the "trick" problem 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:

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

Alternatively, you can do:
- $ 0.7 \text{ mg} \times 6 = 4.2 \text{ mg} $
- Then convert: $ 4.2 \text{ mg} = 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 a unit conversion question.

We know:
- 1 minute = 60 seconds
- 1 hour = 60 minutes

So:
$$
60 \text{ min/hour} \times 60 \text{ sec/min} = 3600 \text{ seconds}
$$

Wait — this is multiplication! But let’s think: Is it really?

Yes, it's multiplying two known quantities (60 × 60), so technically it is a multiplication problem.

But here's the catch: It doesn't involve a variable or scaling based on a given quantity, like "how many seconds in 2 hours?" This one is asking for a standard fact.

Still, the calculation involves multiplication.

But let's keep going — maybe there's another one that's clearly not multiplication.

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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?

This is a division problem.

We need to find thickness per sheet:

$$
\frac{5 \text{ mm}}{100} = 0.05 \text{ mm per sheet}
$$

✘ NOT a multiplication problem! This is division.

This is the trick problem.

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8) A pack of pens contains 8 pens. A box contains 20 packets. How many pens in 5 boxes?

Step-by-step:
- Pens per packet: 8
- Packets per box: 20 → So pens per box: $ 8 \times 20 = 160 $
- Pens in 5 boxes: $ 160 \times 5 = 800 $

Or all at once: $ 8 \times 20 \times 5 = 800 $

✔ Multiplication problem.

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✔ Final Answer:

The trick problem is #7, because it requires division, not multiplication.

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

This asks for a unit rate (thickness per sheet), which is solved by dividing total thickness by number of sheets.

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🔍 Summary of Answers:

| Problem | Solution | Type |
|--------|---------|------|
| 1 | 3600 km | Multiplication |
| 2 | 0.0042 g | Multiplication |
| 3 | 4 pints | Multiplication |
| 4 | 3600 seconds | Multiplication |
| 5 | 3600 m | Multiplication |
| 6 | 5.4 lb | Multiplication |
| 7 | 0.05 mm | ✘ Division (Trick!) |
| 8 | 800 pens | Multiplication |

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✔ Answer: The trick problem is #7. It is not a multiplication problem — it's a division problem.