Lesson: Addition Strategies for Sums to 20: Doubles Minus One

In this lesson, we will learn how to use facts about doubles to add two consecutive numbers whose sum is within 20.

Sample Question Videos

Q1:

Which expression is equal to 6 + 5?

Q2:

Notice that 3 is one less than 4.

So the answer to is one less than the answer to .

If , which of the following is equal to ?

Q3:

Use

to find

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