Subtracting Integers

This video teaches how to subtract integers using different methods such as adding the opposite and the two-pencil stroke method. The concept of the opposite of a number is explained and visual models using counters are shown to help understand the reason why these methods work. Examples are given to illustrate the steps involved in subtracting and the transcript also explains why subtracting is the same as adding the opposite of a number.

Shows how to subtract postive and negative numbers; uses counters. Explains adding the opposite and two stroke method.

• 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?