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3rd grade math · Unit 7: Measurement and time

Time is not base ten

What this lesson shows

Fixes a mistake

9:55 to 10:05 is 10 minutes, not 50. An hour has 60 minutes.

The worked example

The lesson works this one step by step: 9:55 a.m. to 10:05 a.m. Then your kid tries one like it on paper.

The steps

  1. Not like whole numbers
  2. An hour is 60 minutes
  3. Count up across the hour

Helping at home

Never subtract the times as plain numbers. Count up on a number line: to the next whole hour first, then the minutes past it. An hour has 60 minutes.

If your kid gets stuck

Count up to the hour 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

Standards

  • Common Core 3.MD.A.1
    Tell and write time to the nearest minute and measure time intervals in minutes. Solve word problems involving addition and subtraction of time intervals in minutes, e.g., by representing the problem on a number line diagram.
Matches standards in 50 statesSee each state's code

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