Exercise 86 Page 87

According to the order of operations, expressions inside parentheses are evaluated first, while addition and subtraction are evaluated last. For the given expression, this means evaluating the expression inside the square brackets completely before solving the product. 2[2-(2-3)-2]

Notice also that even within this square brackets expression, we must obey the order of operations. 2-(2-3)-2 For this, we must remember to evaluate the expression inside the parentheses first and the subtraction later.

Operation	Before Simplification	After Simplification
Subtract terms	2[2-( 2-3)-2]	2[2-(- 1)-2]
- (- a)=a	2[2-(- 1)-2]	2[2+ 1-2]
Add and subtract terms	2[ 2+1-2]	2[ 1]
Multiply	2[ 1]	2

The expression equals 2.

Alternative Solution

Using a Calculator

We can also evaluate this expression using a calculator. To do so, type it as shown below.