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3rd grade math · Unit 7: Measurement and time

Scarce things cost more

What this lesson shows

Lemons cost 25¢ each in summer, when there are plenty, and 50¢ after a frost, when few are left. When a resource is scarce, its cost goes up; when it is plentiful, its cost goes down.

The worked example

The lesson works this one step by step: lemons at 25¢, then 50¢, buy 4. Then your kid tries one like it on paper.

The steps

  1. Plenty: the cost goes down
  2. Scarce, few left: the cost goes up
  3. How many × price each = the cost

Helping at home

Read each story aloud. Your kid subtracts to find how much more one costs when few are left, then multiplies to price the whole buy both times.

If your kid gets stuck

Subtract the prices, then multiply by how many.

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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