Length and centimetres · Usually met around P1
Measuring with things
From one end, no gaps, no overlaps.
How to do it
Method
From one end, no gaps, no overlaps
The strip = 6 paper clips long
Another way
Compare with the same thing
A 8 clips, B 5 → A is longer
In full
You can measure a length with copies of one thing laid end to end: paper clips, cubes, hand spans, footsteps… Count how many you used: the strip is 6 paper clips long, say. Start at one end and lay them touching, with no gaps and no overlaps. To compare two things, measure both with the same thing; a longer thing to measure with gives a smaller number. If A is longer than B and B is longer than C, then A must be longer than C.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
How many 📎 long is the strip?
Show the answer and working
Answer: 12
The 📎 lie end to end under the strip; count them: 12.
Example 2
Ka-yan measures a desk with 🍌 and gets 13; Tsz-ching measures the same desk with 📎 and gets 5. A 🍌 is longer than a 📎.
True or false?
Show the answer and working
Answer: False
For the same desk, the longer the thing you measure with, the fewer you need.
Example 3
Measured with 🧊: strip A is 12 long and strip B is 11. How many 🧊 longer is A than B?
Show the answer and working
Answer: 1
12 − 11 = 1.
Practise it in the game →Length and centimetres · Free to start, unlimited questions, no download