+24 + 3 * -4 ------ +24 + -12 ----------- 12

The first `+`

is a unary plus,
so it has high precedence and applies only to the 24.

The `-`

is a unary minus,
so it applies only to the 4.

Next in order of precedence is the `*`

,
so three times negative four is calculated yielding negative twelve.

Finally the low precedence `+`

combines the positive twenty four with the negative twelve.

To show exactly what numbers go with each operator, use parentheses. For example

-1 * ( 9 - 2 ) * 3

means do 9 - 2 first. The `( )`

groups together what you
want done first.
After doing the subtraction, the ( 9 - 2 ) becomes a 7:

-1 * 7 * 3

Now follow the left-to-right rule for operators of equal precedence:

-1 * 7 * 3 ------ -7 * 3 -------- -21

What is the value of each of the following expressions?