*numbers*or

*variables*(letters). The most commonly used grouping symbols are

**parentheses.**Operations inside parentheses can be done before any other operations in order to simplify the problem.

##### Example 1

Simplify 4(3 + 5).

##### Example 2

Simplify (2 + 5)(3 + 4).

**Brackets** and **braces** are less commonly used grouping symbols and should be used after parentheses. Parentheses are to be used first, then brackets, and then braces: { [ ( ) ] }. Sometimes, instead of brackets or braces, you will see the use of larger parentheses.

##### Example 3

Simplify ((2+3) × 4) + 1.

An expression using all three grouping symbols looks like this:

2{1 + [4(2+1) + 3]}

##### Example 4

Simplify 2{1 + [4(2+1) + 3]}.

Notice that you work from the inside out.