Math 7 · Unit 3, Lesson 2
Subtracting Signed Numbers
Subtracting means adding the opposite
ElleMath-speak
In this lesson, we subtract signed numbers by adding the opposite.
FinnPlain English
Don't ever subtract signed numbers. Change the problem to adding, then add.
Write it down. Do every change on paper, one line per step. Changing signs in your head is the number one reason for missed problems. If you changed something, it should be on the paper.
This lesson is one tile, on purpose: one rule, said plainly and practiced until it sticks. It has a short explanation, then a "Let me try a few" button.
When you have finished
At the end of each tile you will find a review form to give us feedback.
NC standard: NC.7.NS.1.