The “Keep-Change-Change” Rule

To solve any integer subtraction problem, follow these three steps:

1. Keep the first number exactly the same.

2. Change the subtraction sign (-) into an addition sign (+).

3. Change the sign of the second number to its opposite (if it is positive, make it negative; if it is negative, make it positive).

After doing this, you just follow the normal rules for adding integers!

Examples

• Positive minus a Positive: 7 – 10 becomes 7 + (-10) = -3

• Positive minus a Negative: 5 – (-4) becomes 5 + 4 = 9

• Negative minus a Positive: -6 – 2 becomes -6 + (-2) = -8

• Negative minus a Negative: -8 – (-3) becomes -8 + 3 = -5

Topics Covered:
1) Subtracting positive integers from positive integers
2) Subtracting negative integers from negative integers
3) Subtracting negative integers from positive integers
4) Subtracting positive integers from negative integers
5) Real-life problems
6) Problems involving temperature, altitude, and depth
7) Distance calculation problems
Proficiency Levels:
Excellent (90-100%): Expert level in integer subtraction
Very Good (70-89%): Good grasp of the topic; minor gaps remain
Good (50-69%): Understands basic concepts; needs practice
Needs Improvement (0-49%): Review of the topic is recommended
⚡ During the Test:
Read each question carefully
Select an answer by clicking on the options
Receive instant feedback
Navigate using the forward/back buttons
Click the “Finish Test” button on the final question