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 1 chapters and video availability01 · Read and understand
What you will learn
- Add a group of ten to a two-digit count.
- Explain your method and check what the result means in the stated situation.
Before you start
Recognizing small groups and saying counting words; an adult may read the prompts aloud.
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
There are 23 blocks and a bundle of 10 is added. How many blocks?
Why this math matters
Update an inventory quickly when another ten-pack arrives. 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.
Add ten without changing the ones
PausedQuestion: Start with the question. Paused.
Question
Start with the question
There are 23 blocks and a bundle of 10 is added. How many blocks?
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
23 = 2 tens + 3 ones
Separate the original count by place.
Connect the parts
2 tens + 1 ten = 3 tens
The new bundle changes only the tens.
State and check the result
23 + 10 = 33
The three original ones remain.
The result
23 + 10 = 33
The three original ones remain.
Common mistakes to catch
- Adding ten is not adding one to the ones digit.
- Keep the ones count unchanged for this operation.
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 46 + 10.
Show a hint
Increase the tens by one.
Reveal answer and explanation
56
Four tens become five tens, with six ones.
Practice 2
A number becomes 38 after adding ten. What was it?
Show a hint
Remove one ten.
Reveal answer and explanation
28
Three tens minus one ten leaves two tens and eight ones.
Take the idea with you
Update an inventory quickly when another ten-pack arrives.
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: Order objects by length
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