Question

Select the correct answer.

A mistake was made in the steps shown to simplify the expression. Which step includes the mistake?

A.
Step 4
B.
Step 5
C.
Step 1
D.
Step 3

Answer 1

Answer: Step 5

===================================================

Reason:

The order of operations is PEMDAS

• P = parenthesis
• E = exponents
• M = multiplication
• D = division
• A = addition
• S = subtraction

The multiplication and division are on the same level of precedent, and the same goes for addition and subtraction. Some math textbooks may refer to PEMDAS as BODMAS, which is basically the same thing.

Notice how division comes before addition. So we must compute the
`10 / 2` portion first before adding in step 4.

This is what steps 4 and onward should look like

`2 + 10 / 2\\\\2 + 5\\\\7`

So that's why the error is in step 5

If there was parenthesis around the "2+10", and we had
`(2+10) / 2`, then step 5 given by your teacher would be correct.