Big Ideas Math: Modeling Real Life, Grade 6
BI
Big Ideas Math: Modeling Real Life, Grade 6 View details
7. Dividing Decimals
Continue to next subchapter

Exercise 5 Page 92

Pay close attention to the order of operations.

B

Practice makes perfect
According to the order of operations, expressions inside parentheses are evaluated first, followed by exponents, then multiplication and division, and finally addition and subtraction are evaluated last. We can use the acronym PEMDAS to help us remember the correct order!
pemdas
For the given expression, this means evaluating the expression inside the square brackets completely before adding the product.

18+3^2Ă· [3* (8-5)] Notice also that even within this parenthetical expression, we must follow the order of operations. 3* (8-5) Let's do it!

Operation Before Simplification After Simplification
Subtraction inside parentheses 18+3^2Ă· [3* ( 8- 5)] 18+3^2Ă· [3* ( 3)]
Multiplication inside square brackets 18+3^2Ă· [ 3* 3] 18+3^2Ă· 9
Calculate power 18+3^2Ă· 9 18+ 9Ă· 9
Divide 18+ 9Ă· 9) 18+ 1
Add terms 18+ 1 19
The expression is equal to 19. Therefore, the correct option is B.

Alternative Solution

Using a Calculator

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

Whenever using a calculator for a complicated expression such as this, be very careful when placing the parentheses. A calculator will only do what it is told to do, not what you meant for it do.