Understand the idea.
Count gaps, not marks
On an evenly divided scale, equal spaces represent equal changes in value. Choose two labelled marks, find their value difference and count the gaps between them. Divide that difference by the number of gaps to find one gap.
Count spaces rather than tick marks. Five gaps have six boundary marks. From 0 to 1000 grams in five gaps, each gap is , giving readings of 0, 200, 400, 600, 800 and 1000 grams.
Read from a known label
Start at a labelled value and count equal-sized jumps to the pointer. On the mass scale, three gaps from zero mean three groups of 200 grams. Write the unit shown on that scale, not just the number.
Check your reading against the labels on either side. On a real instrument, look straight at the pointer or liquid level so your viewing angle does not shift the apparent reading.
See the method in action.
Read a mass scale
Read the pointer on this mass scale.
Worked solution
- 1
Find the value of one gap.
The difference from 0 to 1000 grams is spread across five equal gaps.
- 2
Count from zero to the pointer.
The pointer is at the third gap after the zero mark, not the third tick including zero.
- 3
Calculate the reading.
Each of the three gaps adds 200 grams.
600 g.
Read an unnumbered tick
Read the pointer on the millilitre scale.
Worked solution
- 1
Use the labelled 0-to-100 section.
Two equal gaps separate 0 and 100, so the unnumbered ticks count in fifties.
- 2
Find the nearby label.
The pointer is one gap after the labelled 300 mark.
- 3
Add one gap.
The pointer lies halfway between 300 and 400 millilitres.
350 mL.
Try it yourself.
Check your understanding
A scale has four equal gaps from 0 to 80 mL. What is one gap worth?
Show answer & reasoning
20 mL
The total change is 80 mL across four equal gaps. One gap is therefore . Four steps of 20 return to 80.
Keep practising
6 worksheet questions · 11 marks
Read the questions online
- A ruler has 10 equal gaps from 0 to 10 cm. What does each gap represent?1 mark
- Read the mass pointer.2 marks
- Read the liquid pointer.2 marks
- A scale has five equal gaps from 0 to 50 kg. A pointer is four gaps from 0. Find the mass.2 marks
- A temperature scale rises from 10 °C to 30 °C in four equal gaps. Give the values at all five marks.2 marks
- A learner counts the two marks labelled 0 and 10 as two intervals. Explain why that is wrong.2 marks
Read the worked solutions
Equivalent correct methods earn the corresponding marks. Include units where asked.
- A ruler has 10 equal gaps from 0 to 10 cm. What does each gap represent?1 mark
cm.
1 cm - Read the mass pointer.2 marks
Five gaps cover 1000 g, so each is 200 g.
The pointer is four gaps from 0: g.
800 g - Read the liquid pointer.2 marks
Each small gap is 50 mL.
One gap after 400 is 450 mL.
450 mL - A scale has five equal gaps from 0 to 50 kg. A pointer is four gaps from 0. Find the mass.2 marks
kg each.
kg.
40 kg - A temperature scale rises from 10 °C to 30 °C in four equal gaps. Give the values at all five marks.2 marks
The difference is 20 °C.
°C per gap.
10, 15, 20, 25, 30 °C - A learner counts the two marks labelled 0 and 10 as two intervals. Explain why that is wrong.2 marks
Intervals are spaces between marks, not the marks themselves.
There is one gap between those two marks.
Curriculum reference & lesson scope
Australian Curriculum v9 and SA Curriculum Mathematics 2026
Length/mass/capacity/temperature; scaled instruments; partial/unmarked intervals; suitable units and accuracy.
Official curriculum source ↗