Today is rung 5 of 5 on this topic
Unit conversion and measurement problems
Can do: Converts between units — cm and m, g and kg, minutes and hours — and uses them in problems.
Why it matters
Conversion is multiplicative reasoning applied to the real world, and it's the source of a large share of lost marks in tests.
What it looks like when it's wobbly
Divides when they should multiply, ending up with 3 km = 3,000,000 m or 0.003 m.
⏱️ Two-minute check
"How many grams in 2.5 kg? How many minutes in 3.5 hours?"
Solid looks like: 2500 g and 210 minutes.
The full activity for this topic · 15 minutes
Bigger or Smaller Number?
- 1Teach the sanity check first: going to a smaller unit always means a bigger number.
- 2Weigh and measure real things and record them in two units each.
- 3Convert a recipe from kilograms to grams and cook it.
- 4Do a mixed set on paper, saying "bigger or smaller?" out loud before each one.
- 5Add times: how many minutes in the school day, in a week of screen time.
If it's too hard
One conversion type at a time with real objects.
If it's too easy
Two-step problems where units must be converted before the sum can be done.
Say this
"Grams are smaller than kilograms. So will the number get bigger or smaller?"