Skill: Write equations from stories

To write an equation from a story:

1. Find the quantities you know.
2. Decide what is happening: are you joining, separating, or comparing?
3. Find what is unknown.
4. Use a box for the unknown.

Example

Mia has 27 stickers. She gives 9 stickers to her friend. How many stickers does Mia have left?

• Mia starts with $(27)$ stickers.
• She gives away $9$, so the number gets smaller.
• The unknown is how many stickers are left.
• Use subtraction:

$$27 - 9 = \square$$

The box stands for the number of stickers left. The equal sign means that $(27 - 9)$ and the number in the box have the same value.

Solving the equation:

$$27 - 9 = 18$$

So, Mia has $(18)$ stickers left.