Lesson: Subtracting by Counting Back: Numbers up to 20 Mathematics • 1st Grade

In this lesson, we will learn how to subtract within 20 by counting back from the starting number.

Lesson Video

Q1:

On this domino, the dots on one side are covered with a sticker, and the total number of dots is written above it.

How many dots are under the sticker on this domino?

Q2:

Michael holds up 9 fingers and starts counting down as he puts down one finger at a time. He stops when he is holding up 4 fingers.

Decide whether he was adding or subtracting by picking the number sentence that describes what he did.

Q3:

Emma put her counter on 12 then moved it back 2 spaces.