Question

You decide to give 18 of your card collection to your little brother. How much of your collection do you have left?

Answer 1

The equation would be

x - 18 = collection left

X = how much was your collection before you gave your brother 13 cards

Since we don't know how big was your collection before, this would be the equation to solve it.

Answer 2

The answer is
`C-18`

Explanation:

In order to determine the answer, we have to build the expression that represents the remain collection.

According to the statement, we do not know the initial collection, but we can express this amount with a variable:

C=initial collection cards

Then, we know that we have to give 18 card to the little brother, so we have to subtract 18 to the initial collection.

The expression for the remain cards is:

`C-18`