Lesson: Doubles Minus One Mathematics • 1st Grade

In this lesson, we will learn how to add two consecutive numbers with sums up to 20 by finding one less than a doubles fact.

Sample Question Videos

Q1:

Notice that 3 is one less than 4.

If , which of the following is equal to ?

Q2:

Use

Q3:

Amelia tried to solve by using the doubling numbers facts, but she got the answer wrong.

Her teacher circled the mistake in her answer. Help her by finding .

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