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Teaching video
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Grade 5 chapters and video availability01 · Read and understand
What you will learn
- Explain decimal scaling through place-value changes.
- Explain your method and check what the result means in the stated situation.
Before you start
Multi-digit operations, equivalent fractions, decimal place value, and rectangular area.
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
Find 3.47 × 100 and 3.47 ÷ 10.
Why this math matters
Check metric conversions by asking whether the numerical count should grow or shrink. 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.
Scale decimals by powers of ten
PausedQuestion: Start with the question. Paused.
Question
Start with the question
Find 3.47 × 100 and 3.47 ÷ 10.
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
×100 makes each value one hundred times as large
Each digit occupies a place two positions larger.
Connect the parts
÷10 makes each value one tenth as large
Each digit occupies a place one position smaller.
State and check the result
3.47 × 100 = 347; 3.47 ÷ 10 = 0.347
Zeros fill any newly empty places.
The result
3.47 × 100 = 347; 3.47 ÷ 10 = 0.347
Zeros fill any newly empty places.
Common mistakes to catch
- Explain changing digit values instead of merely saying the point moves.
- Division by ten makes positive values smaller.
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
Find 0.056 × 1,000.
Show a hint
Each digit shifts three place values larger.
Reveal answer and explanation
56
Fifty-six thousandths multiplied by one thousand becomes fifty-six.
Practice 2
Why does multiplying 0.4 by ten give 4 rather than 0.40?
Show a hint
A trailing zero does not multiply value.
Reveal answer and explanation
Four tenths must become four ones
0.40 is still four tenths, while 4 is ten times larger.
Take the idea with you
Check metric conversions by asking whether the numerical count should grow or shrink.
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: Multiply a decimal by a whole count
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