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Practice

How can we count back to subtract?

Goal:

Goal:

thinking monkey

Think About It!

Goal: How does counting back help us subtract?

When we count backwards to subtract, we use the counting-back strategy. This means we will count backwards to find the difference!

First, let’s make sure we are comfortable counting backwards from 10 to 1. Start with the last leaf in the row, and click the leaves next to it to see them count back from 10.

A leaf with an 'x' on it, and the number 10
A leaf with an 'x' on it, and the number 9
A leaf with an 'x' on it, and the number 8
A leaf with an 'x' on it, and the number 7
A leaf with an 'x' on it, and the number 6
A leaf with an 'x' on it, and the number 5
A leaf with an 'x' on it, and the number 4
A leaf with an 'x' on it, and the number 3
A leaf with an 'x' on it, and the number 2
A leaf with an 'x' on it, and the number 1

Great job! Now let’s try counting back to subtract 6 - 2. Here are the steps to count back:

  1. Say the whole number.

    We will start counting backwards from the whole because that is where we always start when we subtract. In your head, think of the number 6.

  2. Put up as many fingers as the number you are taking away. Since we are taking away 2, put up 2 fingers, like this:

    A hand, with two fingers up. The index and the middle finger. Also known as, a peace sign.

  3. Now we are going to count backwards using our fingers. Since we started with 6 and are counting back 2 times, wiggle one finger and count back once to 5. Then, wiggle the other finger and count back again from 5 to 4.

A hand, with two fingers up. The index and the middle finger. Also known as, a peace sign.

That means 6 - 2 = 4!