Skill: Solve multiplication word problems

When a word problem describes equal groups, use multiplication.

Look for:

• Number of groups
• Amount in each group
• Total amount, which is the product

Example

A school has $24$ boxes of pencils. Each box contains $18$ pencils. How many pencils are there altogether?

1. Identify the quantities and units.

• $24$ boxes = number of groups
• $18$ pencils per box = amount in each group
• The answer will be in pencils

Because every box has the same number of pencils, this is a multiplication problem.

2. Write a multiplication equation.

$$24 \times 18 = \text{number of pencils}$$

3. Multiply.

$$\begin{aligned} 24 \times 18 &= 24 \times (10+8)\\ &= (24 \times 10)+(24 \times 8)\\ &= 240+192\\ &= 432 \end{aligned}$$

4. Write the answer with its unit.

There are $432$ pencils altogether.

5. Check whether the answer is reasonable.

Since $18$ is close to $20$, estimate:

$$24 \times 20=480$$

The exact answer, $432$, is close to $480$, so it is reasonable.