Practice 1
Answer & reasoning
0.01 · The span is 0.1; one tenth of that span is 0.01.
Read the scale before naming a decimal point
Find the value of one interval from the labelled endpoints, then count the travelled intervals.
Try the practice questionsStart with this question
A line from 0.3 to 0.4 is split into ten equal intervals. What is the third point after 0.3?
The key idea: 0.33. The displayed span is one tenth, so each of its ten equal intervals is one hundredth.
Make the idea visible
- Read both endpoints: the span from 0.3 to 0.4 is 0.1, not one whole.
- Partition 0.1 into ten equal distances. Each distance is 0.01. Eleven tick marks enclose the ten intervals.
- Start at 0.30 and travel three intervals: 0.31, 0.32, 0.33. Do not count the starting tick as the first travelled step.
- Check that 0.33 lies between the labelled endpoints and is closer to 0.3. Label the point at the endpoint of the third interval.
A useful error to discuss
A learner might say: Ten intervals always mean steps of one tenth.
Ten intervals divide the displayed span, which may be smaller or larger than one whole. Subtract the endpoint values before dividing by the interval count.
Practise, then check
Try the first three questions with the model. Try the final check without help. A correct value is a starting point: explain how your units or drawing support it.
Practice 2
Answer & reasoning
0.25 · Five hundredths beyond twenty hundredths is twenty-five hundredths.
Practice 3
Answer & reasoning
0.1 · This displayed span is a whole, so each interval is one tenth.
Independent check
Answer & reasoning
0.76 · Six hundredths beyond 0.70 is 0.76.
Explain a new situation
A line from 0.40 to 0.50 has five equal intervals. Explain why each interval is 0.02.
Discuss the explanation
The span is 0.10. Five equal parts of that span are 0.10 ÷ 5 = 0.02 each.
Materials for your group
Student pages and teacher answers are separate. Download an HTML file to keep or use your browser to print or save as PDF.
Choose the next step
If the learner uses the number of ticks as the denominator, revisit intervals. If the scale is correct, change the displayed span while keeping the same interval count.
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