Learn with Amar
Teaching video
A teaching recording for this chapter has not been published yet. Start with the worked example below and explore the related animations where available.
Grade 2 chapters and video availability01 · Read and understand
What you will learn
- Locate a number between labeled tens on an equally spaced number line.
- Explain your method and check what the result means in the stated situation.
Before you start
Counting and comparing whole numbers, basic addition and subtraction, and recognizing simple shapes.
Keep paper nearby. Read the question once for the context, then again to identify what is known and what you need to find.
Start with a question
A line marks 40 and 50 with ten equal unit steps between them. Where is 46?
Why this math matters
Read a scale by identifying how much each equal gap represents. The worked example shows how to connect the situation, its mathematical representation, and a check on the result.
Set up the model
A useful answer starts with clear assumptions:
- Use the units, grouping rules, and reference whole stated in the question.
- Treat the supplied counts and measurements as exact within the classroom model, unless an estimate or a random outcome is requested.
02 · Work through the example
Follow the reasoning, one step at a time.
Try to predict the next step before reading it. After each calculation, explain why the operation makes sense and how it helps answer the original question.
Work through it with Amar
See this example unfold.
The complete worked example, one idea at a time.
Find positions on a hundred line
PausedQuestion: Start with the question. Paused.
Question
Start with the question
A line marks 40 and 50 with ten equal unit steps between them. Where is 46?
Before you calculate
Read what is known and what you need to find. Make a prediction before moving to the first calculation.
Starts paused. Play advances through the full text at a reading pace; pause whenever you need more time. Previous, Next, and the phase buttons let you set your own pace. Playback pauses when this walkthrough leaves the screen or you switch tabs.
Your device’s reduced-motion setting keeps each phase still. Manual controls remain available. The full written solution stays below.
Represent the situation
50 − 40 = 10
The ten intervals each represent one unit.
Connect the parts
46 − 40 = 6
Move six intervals right from forty.
State and check the result
46 is 6 steps after 40 and 4 before 50
Both distances agree because six plus four makes ten.
The result
46 is 6 steps after 40 and 4 before 50
Both distances agree because six plus four makes ten.
Common mistakes to catch
- Ten tick marks do not necessarily create ten intervals.
- Check the value of one interval before counting steps.
03 · Practice independently
Try it before revealing the answer.
Use paper or a calculator as needed. Write your units and reasoning, then open the hint or explanation to check your approach.
Practice 1
Which number is three unit steps after 70?
Show a hint
Add three to seventy.
Reveal answer and explanation
73
70 + 3 = 73.
Practice 2
How far apart are 58 and 64 on a unit number line?
Show a hint
Count intervals rather than tick marks.
Reveal answer and explanation
6 units
64 − 58 = 6.
Take the idea with you
Read a scale by identifying how much each equal gap represents.
04 · Reflect and continue
Can you explain it in your own words?
Before moving on, explain the main idea without looking at the worked example. Try both practice questions, check your reasoning, and name one mistake you now know how to avoid. Return to a step if you still need support.
Up next: Count by twos and fives
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