7904 views, 3 ratings - 00:10:47
Part of video series Operations with Integers
More free YouTube videos by Julie Harland are organized at http://yourmathgal.com
( download video )
Shows how to subtract postive and negative numbers; uses counters. Explains adding the opposite and two stroke method.
- Minus Mission - Game from Math Game Time: Minus Mission is a free math game providing practice in subtraction in a creeping slime theme. Large green slime at the top of the screen drips blobs with subtraction problems toward a robot at the bottom. Kids must fire at the slime with the correct answer.
- How do you subtract positive and negative numbers?
- What does it mean to subtract positive and negative numbers?
- What are the formal rules for subtracting positive and negative integers?
- What does it mean to take the opposite of a number?
- How do you rewrite a subtraction problem as an addition problem?
- How do you rewrite 2 - 5 as 2 + -5?
- Why can you rewrite 2 - (-5) as 2 + 5?
- How do you rewrite -2 - 5 as an addition problem?
- How can you change subtraction into addition by making two pencil marks?
- What is the Two Pencil Stroke Method and why does it work?
- How can you subtract -27 - 8 by adding the opposite?
- How do you subtract 14 - 19?
- How do you know if -8 - (-11) will be positive or negative?
- What is an easy way to change subtraction to addition, and why does it work?
- How could you draw a picture of -2 - 3 using - and + signs?
- What does it mean to take 6 away from 2?
This lesson shows how to rewrite any integer subtraction problem as an addition problem so the same rules and techniques shown in the adding integers lesson can be used. Many example problems are shown to further solidify this concept. The theory behind why subtracting is the same as adding the opposite is explained as well.
I really liked this VID