Evaluating Numerical Expressions

Evaluating Numerical Expressions

How can you use the Order of Operations to evaluate expressions with decimals?

How can you evaluate expressions with brackets and variables?

 $\left[6\left(x-3.5\right)\right]\div12+4.2$  

 $\left[6\left(x-3.5\right)\right]\div12+4.2$       x = 9.5

• Inside parenthesis first (x - 9.5)

• Substitute 9.5 for x.

• (9.5 - 3.5) = 6

• Rewrite the new expression.

 $\left[6\times6\right]\div12+4.2$  

• Brackets next.

• [6 x 6] = 36

• Rewrite the new expression.

 $36\div12+4.2$  

• Division is next.

•  $36\div12$   = 3

• Rewrite the new expression.

 $3+4.2$  

• Complete addition, the last step. 

• 3 + 4.2 = 7.2

Now, you try.

Remember to follow PEMDAS

Multiple Choice

 $\left(7.8\div2\right)\times12$  

• 46.8

• 117.6

• 69.6

• 15.9

Multiple Choice

 $5.6+\left(3\times9.6-4.8\right)$  

• 20

• 77.76

• 41.28

• 29.6

Multiple Choice

 $\left[\left(4.2\times3.4\right)-9.28\right]$  

• 16.88

• 5

• 1.5

• 24.7

Poll

How confident are you with evaluating numerical expressions?

• I feel great!

• I feeling okay.

• I am confused.