Question

Evaluate expressStephen tried to evaluate the expression (8 + 6 x 2) - 4. His work is below.[8 + 6 x 2] =4Step 1: = [8+ 12) = 4Step 2:= 8 +3Step 3:= 11In which step did Stephen first make a mistake?Choose 1 answer:Step 1Step 2Step 3

Answer 1

Step 1

State the rule for solving such expressions

$\begin{gathered} \text{PEMDAS} \\ P-\text{Parenthesis} \\ E-\text{exponential} \\ M-Mu\text{ltiplication} \\ D-\text{Division} \\ A-\text{ Addition} \\ S-\text{ Subtraction} \end{gathered}$

Step 2

Find Stephen's mistake

From the expression

$\begin{gathered} \lbrack8+6\times2\rbrack\div4 \\ \text{Stephen will try to clear the parenthesis first and to do so he must multiply within the parenthesis first} \\ \lbrack8+12\rbrack\div4 \\ \text{Hence, his first step is right} \end{gathered}$$\begin{gathered} Next,\text{ he will go further to clear the remains of the parenthesis by adding 8 to 12}. \\ 20\div4 \\ \text{Instead he failed to clear the parenthesis totally, dividing 12 in the parenthesis by 4.} \end{gathered}$

This wrongly made his step 2 to be 8 + 3.

Hence, the first mistake he made was in step 2