Exercise 11 Page 50

According to the order of operations, expressions inside parentheses are evaluated first. For the given expression, this means evaluating the expression inside the square brackets completely before dividing. Notice also that even within this parenthetical expression, we must obey the order of operations.

$$\begin{array}{c}28-(16+3)\end{array}$$

For this, we must remember to evaluate the addition inside the parentheses first and finally the subtraction between $28$ and the sum.

Operation	Before Simplification	After Simplification
Add terms	$\left[28-(16+3)\right]÷3$	$\left[28-19\right]÷3$
Subtract term	$\left[28-19\right]÷3$	$9÷3$
Calculate quotient	$9÷3$	$3$

The expression equals $3.$

Alternative Solution

Using a Calculator

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