# Interactive video lesson plan for: How to turn a subtraction of integers into addition - and WHY it works

#### Activity overview:

In this pre-algebra or grade 7 math lesson, I show how integer subtraction works, first of all, based on two simple patterns. If we continue them logically, we see that subtracting an integer works the same as adding the opposite of that integer. The second pattern makes it especially easy to see WHY subtracting a negative integer changes into addition. It's the shortcut of a double negative turning into a positive.

Then I solve several simple examples, such as -6 - (-2) and others. Next, I show how subtraction of integers works on a NUMBER LINE (as jumps).

In the latter part, we study more complex examples of mixed integer additions and subtractions. With those, you can either solve the operations one by one (from left to right) -- or convert each subtraction into an addition first, then add all the positives separately and all the negatives separately, and lastly add the two sums.

Tengo una versión español de este video que se halla en https://www.youtube.com/watch?v=uifGW27ywJs

If you like the video, subscribe to my channel. :) Thanks in advance!

Learn more pre-algebra with Math Mammoth Grade 7 Curriculum at http://www.mathmammoth.com/complete/grade_7.php - available as an instant download and as printed copies. Check out the free samples also!

Tagged under: Integer,Subtraction,Addition,Mathematics (Field Of Study),7th grade,math,pre-algebra,Algebra (Field Of Study)

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