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1st grade math · Unit 5: Adding and subtracting with tens

The ten you opened is gone

What this lesson shows

Fixes a mistake

After opening a ten in 32 − 8, 2 tens are left, not 3. 24, not 34.

The worked example

The lesson works this one step by step: 41 − 6 = □. Then your kid tries one like it on paper.

The steps

  1. Open a ten
  2. Cross out the opened rod
  3. Count the tens left

Helping at home

After trading a ten for 10 ones, cross out the rod. Count only the tens still standing, then the ones left.

If your kid gets stuck

How many tens are still there?

Watch it with Lux

With Lux, this lesson is a narrated video and a printed page your kid works on. Then Lux helps with the same math on their own worksheet, one question at a time.

See how Lux works

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