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4th grade math · Unit 9: Measurement and time

Multiply or divide?

What this lesson shows

Fixes a mistake

5 feet is 60 inches, not 5/12. Estimate which way first.

The worked example

The lesson works this one step by step: 5 feet to inches. Then your kid tries one like it on paper.

The steps

  1. Which unit is smaller?
  2. To smaller: more, multiply
  3. To bigger: fewer, divide
  4. Check the estimate

Helping at home

Before any math, ask which unit is smaller. Going to a smaller unit, there are more of them: multiply. Going to a bigger unit, there are fewer: divide. Check that the answer is bigger or smaller, the way the estimate said.

If your kid gets stuck

Will there be more of the new unit, or fewer?

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 4.MD.A.1
    Know relative sizes of measurement units within one system of units including km, m, cm; kg, g; lb, oz.; l, ml; hr, min, sec. Within a single system of measurement, express measurements in a larger unit in terms of a smaller unit. Record measurement equivalents in a two-column table. For example, know that 1 ft is 12 times as long as 1 in. Express the length of a 4 ft snake as 48 in. Generate a conversion table for feet and inches listing the number pairs (1, 12), (2, 24), (3, 36), ...
  • Common Core 5.MD.A.1
    Convert among different-sized standard measurement units within a given measurement system (e.g., convert 5 cm to 0.05 m), and use these conversions in solving multi-step, real world problems.
Matches standards in 50 statesSee each state's code

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