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
- Round a whole number to the closest multiple of ten.
- 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 class collects 67 leaves. About how many is that to the nearest ten?
Why this math matters
Use rounded counts to judge whether a detailed total is sensible. 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.
Estimate with the nearest ten
PausedQuestion: Start with the question. Paused.
Question
Start with the question
A class collects 67 leaves. About how many is that to the nearest ten?
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
67 lies between 60 and 70
These are the neighboring multiples of ten.
Connect the parts
67 − 60 = 7; 70 − 67 = 3
Compare distances to both choices.
State and check the result
67 rounds to 70
Seventy is closer; the rounded value is an estimate.
The result
67 rounds to 70
Seventy is closer; the rounded value is an estimate.
Common mistakes to catch
- An estimate need not equal the exact count.
- State a tie rule for numbers ending in five.
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
Round 43 to the nearest ten.
Show a hint
Compare distances to forty and fifty.
Reveal answer and explanation
40
Forty is three away; fifty is seven away.
Practice 2
Using the convention that halfway rounds upward, round 85 to the nearest ten.
Show a hint
Eighty-five is equally far from eighty and ninety.
Reveal answer and explanation
90
The stated tie rule chooses ninety.
Take the idea with you
Use rounded counts to judge whether a detailed total is sensible.
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.
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