Jillian is using integer tiles to add 7+(−2). She uses the steps below.

Question

step1. 7+
step2. 7 (-2)
step3. 7+(-2)
step4. 7+(-2)=2
In which step did Jillian make a mistake? Explain in your own words how to correct Jillian's work and what the correct answer is.



NOTE: To receive full credit on this question, you must do three things:

1. State the step in which Jillian made a mistake.

2. Explain how to correct Jillian's work.

3. State the correct final answer.

Answer 1

1. Jillian made a mistake in step 2 when she wrote "7 (-2)". This notation is unclear and does not accurately represent the operation she intended to perform.

2. To correct Jillian's work, she should clearly express the addition of 7 with –2 as "7 + (-2)" from the start. This clarifies that she is adding a negative number (which is equivalent to subtraction). When adding a positive number and a negative number, you should subtract the absolute value of the negative number from the positive number. So, when performing the operation, this can be written as \(7 + (-2) = 7 - 2\).

3. The correct final answer is 5, as \(7 + (-2) = 5\).