Question

jordan tried to evaluate an expression. here is his work:
144 ÷ 12 - 2·4 + 15
= 12 - 2·4 + 15 step 1
= 12 - 8 + 15 step 2
= 4 + 15 step 3
= 19 step 4
is jordans work correct?
no, jordan made a mistake going from the given expression to step 1. jordan should have multiplied 2 and 4 before dividing. the order of operations says to multiply before you divide.
no, jordan made a mistake going from step 2 to step 3. jordan should have added 8 and 15 before subtracting. the order of operations says to add before you subtract.

Explanation:

Step1: Analyze the order of operations

According to the order of operations (PEMDAS: Parentheses, Exponents, Multiplication and Division from left - to - right, Addition and Subtraction from left - to - right), in the expression \(144\div12 - 2\cdot4+15\), multiplication and division should be done from left - to - right first.

Step2: Check Jordan's work

Jordan did \(144\div12\) first (which is correct as division is on the left among multiplication and division operations in the given expression). Then he should have continued with the operations from left - to - right. After \(144\div12 = 12\), the expression becomes \(12-2\cdot4 + 15\). Then \(2\cdot4=8\) (correct). The expression is now \(12 - 8+15\). For addition and subtraction, we should perform them from left - to - right. So \(12-8=4\) (correct), and then \(4 + 15=19\) (correct).

Answer:

Jordan's work is correct.