Learn with Amar
Teaching video
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Grade 3 chapters and video availability01 · Read and understand
What you will learn
- Compute elapsed time across an hour using minutes.
- Explain your method and check what the result means in the stated situation.
Before you start
Place value through hundreds, addition and subtraction, equal groups, and equal shares.
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 workshop begins at 10:38 a.m. and ends at 11:17 a.m. the same day. How long?
Why this math matters
Draw short hops to the next hour when calculating a schedule's duration. 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 duration with a time line
PausedQuestion: Start with the question. Paused.
Question
Start with the question
A workshop begins at 10:38 a.m. and ends at 11:17 a.m. the same day. How long?
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
10:38 to 11:00 = 22 minutes
There are sixty minutes in an hour.
Connect the parts
11:00 to 11:17 = 17 minutes
Add the part after the boundary.
State and check the result
22 + 17 = 39 minutes
The two consecutive intervals exactly span the event.
The result
22 + 17 = 39 minutes
The two consecutive intervals exactly span the event.
Common mistakes to catch
- Do not treat colon notation as a decimal point.
- Check date or morning/evening information when an interval could cross boundaries.
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
A 35-minute lesson starts at 2:45 p.m. When does it end?
Show a hint
Use fifteen minutes to reach three.
Reveal answer and explanation
3:20 p.m.
Twenty of the thirty-five minutes remain after 3:00.
Practice 2
Why is 11:17 − 10:38 not found by ordinary decimal subtraction?
Show a hint
Hours use sixty minutes.
Reveal answer and explanation
Clock notation is not base-ten decimal notation
The digits after the colon count sixtieths of an hour, not hundredths.
Take the idea with you
Draw short hops to the next hour when calculating a schedule's duration.
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: Combine mass measurements
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