Join Karin Hutchinson for an in-depth discussion in this video Solution: Subtract integers, part of Learning Algebra: Pre-Algebra.

- Let's walk through the solutions to worksheet #2 together. Letter A is -12 minus 20. For this problem, we're going to use the Keep, Change, Change rule to rewrite this as addition. I'm going to do it right in the problem. So keep -12 the same, change to addition, change to -20. So -12 plus -20 is now an addition problem where the signs are the same. So I'm going to add the numbers and keep the sign.

12 plus 20 is 32, and I'm going to keep the negative sign. So the final answer for letter A is -32. For letter B, we have the problem 18 minus -22. For this problem, we're also going to use Keep, Change, Change. So keep, change, change. This now becomes 18 plus 22. 18 plus 22 is 40, so the answer to letter B is 40.

Letter C, the problem is 25 minus 35 minus -3. For this problem, we're going to start with 25 minus 35, and I'm going to use Keep, Change, Change to make this 25 plus -35. Now my signs are different, and I'm adding, so I'm going to subtract. 35 minus 25 is 10, and since -35 has the larger absolute value, I'm going to keep the negative sign.

Now, I'm going to bring down the minus -3. And again, since I'm subtracting, I need to rewrite this as addition. So -10 plus positive 3 is now an addition problem with signs that are different. So we're going to subtract the numbers. 10 minus 3 is 7, and -10 has the larger absolute value, so it's -7. Therefore, the final answer to letter C is -7.

For letter D, the problem is -25 minus 15 plus -3. We're going to start with -25 minus 15. I'm going to Keep, Change, Change to make this -25 plus -15. This answer is -40. My signs are the same, so I add the numbers and keep the sign. Now we're going to bring down plus -3.

Now I'm adding, my signs are the same, so that means I'm going to add the numbers 40 plus 3 is 43, and I'm going to keep the sign. So the final answer is -43. And Letter E is the problem - 12 minus 10 plus 13 minus -4. For this problem, we're going to start with -12 minus 10.

I'm going to use Keep, Change, Change to make this -12 plus -10, which is -22. Add your numbers and keep your sign. Now we're going to bring down plus 13. - 22 plus 13 is -9. We need to subtract the numbers since the signs are different, and since -22 has the larger absolute value, the answer is negative. Now we're going to bring down the remaining, minus -4.

Since we're subtracting, I'm going to Keep, Change, Change, and this becomes -9 plus 4. I'm adding signs that are different, so 9 minus 4 is 5. - 9 has the larger absolute value, and it's negative. So the final answer for letter E is -5.

###### Released

8/4/2015This course includes practice challenges and worksheets, as well as tips for educators who are helping students master pre-algebra for Common Core. Karin Hutchinson also helps you evaluate, write, and simplify expressions, and solve word problems and complex algebraic expressions.

- Adding integers
- Subtracting
- Multiplying and dividing
- Understanding the order of operations
- Evaluating expressions
- Breaking down word problems and algebraic expressions
- Distributing positive and negative numbers
- Simplifying expressions

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Video: Solution: Subtract integers