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Teaching video
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Grade 4 chapters and video availability01 · Read and understand
What you will learn
- Rename a mixed number when its fractional part is too small to subtract directly.
- Explain your method and check what the result means in the stated situation.
Before you start
Multiplication and division facts, simple fractions, place value, and basic length and area measurement.
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 3¼ − 1¾.
Why this math matters
Use fractional-unit trades just as place-value trades support whole-number subtraction. 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.
Exchange one whole to subtract fractions
PausedQuestion: Start with the question. Paused.
Question
Start with the question
Find 3¼ − 1¾.
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
3¼ = 2 + 5/4
Exchange one whole for four fourths and combine it with the existing fourth.
Connect the parts
(2 − 1) + (5/4 − 3/4)
Subtract matching whole and fractional parts.
State and check the result
1 + 2/4 = 1½
Check by adding one and three fourths back to recover three and one fourth.
The result
1 + 2/4 = 1½
Check by adding one and three fourths back to recover three and one fourth.
Common mistakes to catch
- Exchanging a whole reduces the whole-number part by one.
- Subtract in the given order instead of reversing fractional numerators.
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 2⅕ − ⅘.
Show a hint
Rename two and one fifth as one and six fifths.
Reveal answer and explanation
1⅖
6/5 − 4/5 = 2/5 with one whole left.
Practice 2
Why does 3¼ equal 2 + 5/4?
Show a hint
Four fourths make one whole.
Reveal answer and explanation
One whole was renamed as four fourths
2 + 1 + 1/4 = 3¼, so the value is preserved.
Take the idea with you
Use fractional-unit trades just as place-value trades support whole-number subtraction.
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: Repeat a fractional amount
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