Lesson: Subtraction of 7, 8, or 9 from Teen Numbers

In this lesson, we will learn how to use the decomposition of teen numbers into tens and ones to help subtract 7, 8, or 9 from numbers between 11 and 20.

Sample Question Videos

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Worksheet: 4 Questions • 3 Videos

Q1:

Which addition expression is equal to ?

Q2:

Think about taking away 9 from different numbers.

For example, the pictures show that 10 take away 9 is 1 and 11 take away 9 is .

Look at these number sentences. Which one is WRONG?

Q3:

Let us try to find 13 take away 9.

We can draw 13 dots as one group of 10 dots and one group of 3 dots.

Now take away 9 from the group of ten dots.

We are left with dots which is 4 dots.

So .

Now you have a go. What is ?

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