Concept 1 of 6
Measuring with a Ruler
Today's big idea
Line the end up with 0, then read the number at the other end.
A crayon from 0 to 8 is 8 cm long.
How it works
👀 What's going on?
How long is your pencil? Grab a ruler and find out.
💡 Here's the trick
Line the end of the object up with 0, then read the number at the other end. That number is the length in centimetres (cm).
A crayon starts at 0 and ends at 8. It is 8 cm long.
✍️ Try it
A leaf starts at 0 and ends at 6. How long is it? → 6 cm.
⚠️ Watch out
Always start at 0, not at 1, or your answer will be too big.
Watch me solve one
Quanta solves it
“Watch how I think through one of these — then you try.”
THE PROBLEM
“A leaf lies on a ruler from 0 to 7. How long is it?”
- 1
Check the start
The leaf's end sits right on 0. Good.
- 2
Read the other end
The far end is at 7.
- 3
Answer ✓
7 cm long
Now you try one — same steps, different story 👇
See it in action
⚡ Time to play!
The object starts at 0. Read the number at its other end.
How long is it?
Quick check
✅ VERIFICATION
A stick lines up from 0 to 12 on a ruler. How long is it?
⚡ Finish the activity above first to answer.
Keep going!
Up next: Centimetres & Metres
1 metre is 100 centimetres.