Skill: Represent a problem with an equation

To represent a word problem with an equation:

1. Find the quantities you know.
2. Decide how they are related: joining, separating, comparing, or finding a missing part.
3. Use a question mark for the unknown.
4. Make sure both sides of the equal sign show the same amount.

Example:
Liam has $(36)$ stickers. He wants $(52)$ stickers. How many more stickers does he need?

The known amounts are $(36)$ and $(52)$. The missing amount is the number of stickers needed to get from $(36)$ to $(52)$.

This is a missing-part problem, so we can write:

$$36+?=52$$

The equation says that $(36)$ stickers plus the missing stickers equals $(52)$ stickers.

To find the missing number, count up from $(36)$ to $(52)$:

$$36+16=52$$

So, the answer is:

$$\boxed{16\text{ stickers}}$$

We could also represent the same relationship with subtraction:

$$52-36=16$$

Both equations show that $(16)$ is the difference between $(36)$ and $(52)$.