# Adding and subtracting like terms

Algebraic terms that have the same letter are called like terms. Only like terms can be added or subtracted.

, and are like terms, but , and are not like terms.

When like terms are added and subtracted, it is called simplifying.

## Adding and subtracting like terms

The Khan family and the Norman family visit the zoo together - there are children and adults in the group. Because there are more than people, the families can take advantage of a special offer - child can be admitted free of charge.

As before if we use for the cost of child admission and for the cost of adult admission, then:

Cost for the Khan family

Cost for the Norman family

Offer

Total cost

Simplified

## + and - signs

A term, like a number, belongs with the sign that sits in front of it. So in the expression , the belongs with the sign that sits in front of it, so it is . Similarly, belongs with the sign that sits in front of it, making it .

### Example

Collect all the like terms together for .

Gathering all the s and s together would give .

When you add or subtract terms, keep each term with their or sign.

Question

Simplify

Rewrite the expression by putting the like terms next to each other. Remember to keep the or with the terms they belong to.

Simplify this to get: