17. explain how to evaluate the expression. 45 ÷ (30 + 15) ÷ 5

Explanation:

Step1: Solve innermost parentheses

First, calculate $30 + 15$ inside the innermost parentheses. $30+15 = 45$

Step2: Solve the middle - level operation

Then, calculate $(30 + 15)\div5$, which is now $45\div5$. $45\div5=9$

Step3: Solve the outermost operation

Finally, calculate $45\div[(30 + 15)\div5]$, which is $45\div9$. $45\div9 = 5$

Answer:

5