Cogito
Grade 4 Math · Chapter 7 · Lesson 7
Units of Measurement
Bigger units, smaller numbers.
10 problems · about 15 minutes · 4.MD.A.1, 4.MD.A.2
What this lesson teaches
The child converts between units within one system of measurement.
- A smaller unit needs a bigger number.
- Multiply when converting to a smaller unit.
- Time counts in sixties, not tens.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
2 problemsReview — Lines of Symmetry: How many lines of symmetry does a square have?
Answer 4
Why 4 lines.
Review — Sorting Shapes by Their Angles: How many right angles can a triangle have?
Answer 1
Why Two right angles would use all 180 with nothing left.
Warm Up
Straightforward practice. Get the method working first.
4 problems7 metres in centimetres?
Answer 700
Why 700 centimetres.
How many seconds in a minute?
Answer 60
Why 60 seconds.
5 metres in centimetres?
Answer 500
Why 5 × 100.
4 kilograms in grams?
Answer 4000
Why 4 × 1,000.
Build It Up
The same ideas with more to keep track of.
2 problems2 minutes in seconds?
Answer 120
Why 2 × 60.
Going to a smaller unit, does the number get bigger?
Answer Yes. It takes more of them.
Why Centimetres are smaller than metres.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsThe Bottle: 2 litres in millilitres. How many?
Answer 2000 ml
Why 2,000 millilitres.
The Lesson: 3 hours in minutes. How many?
Answer 180 minutes
Why 180 minutes.