We use parentheses to delimit the part of an expression we want evaluated first. If grouping symbols are nested, evaluate the expression in the innermost pair of grouping symbols first,
## Writing mathematical statements: placement of $=$
We only write one equals sign per line. For example, if we are resolving parentheses:
We call parentheses (`()`), brackets (`[]`) and braces `{}`) grouping symbols. When groupings (say parentheses) are used, the expression inside any pair of parentheses must be evaluated first.