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5th grade math · Unit 11: Expressions and equations

Undo to solve

What this lesson shows

(8 × n) + 155 = 315: take away 155, then divide by 8. n = 20.

The worked example

The lesson works this one step by step: 8 × n + 155 = 315. Then your kid tries one like it on paper.

The steps

  1. Steps done to n
  2. Undo in reverse
  3. Check

Helping at home

Read the equation as steps done to n: times a number, then plus a number. Undo them in the opposite order: subtract first, then divide. Check by putting n back in.

If your kid gets stuck

Undo the last step first.

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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