Question

Jillian is using integer tiles to add 7 + (-2) she uses the steps below

Step 1: + + + + + + +
Step 2: + + + + + + +
- -
Step 3: she cicles the 2 - with the 2 +s above it

Step 4: 7+ (-2) = 2

In which step did Jillian make a mistake?
Explain which step Jillian made a mistake, correct it, and state the correct answer

Answer 1

Jillian made a mistake in Step 4. In her previous steps, she correctly represented the problem using integer tiles, but the final conclusion doesn't accurately reflect the result of the addition.

Let's analyze the steps more closely:

1. **Step 1:** Jillian correctly represents the positive 7 using 7 positive tiles:
+ + + + + + +

2. **Step 2:** She also correctly represents the negative -2 using 2 negative tiles:
- -

3. **Step 3:** She circles 2 negative tiles with 2 of the positive tiles above it, which correctly shows the process of canceling these out. After canceling, she is left with:
+ + + + + (5 remaining positive tiles)

Thus, after canceling, the result should be calculated from the number of remaining positive tiles, which is 5.

So instead of concluding in Step 4 that \( 7 + (-2) = 2 \), the correct conclusion is:

**7 + (-2) = 5.**

Jillian’s final answer should be corrected to reflect that \( 7 + (-2) = 5 \).