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
- Add multi-digit numbers by matching place values without regrouping.
- 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 library has 243 storybooks and 125 information books. What total?
Why this math matters
Combine two inventory lists by adding matching units in columns. 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 hundreds, tens, and ones
PausedQuestion: Start with the question. Paused.
Question
Start with the question
A library has 243 storybooks and 125 information books. What total?
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
200 + 100 = 300
Combine the hundreds.
Connect the parts
40 + 20 = 60; 3 + 5 = 8
Combine tens with tens and ones with ones.
State and check the result
243 + 125 = 368 books
The combined places give three hundreds, six tens, and eight ones.
The result
243 + 125 = 368 books
The combined places give three hundreds, six tens, and eight ones.
Common mistakes to catch
- Align places, not the left edges of numbers.
- A blank hundreds place represents zero hundreds.
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 312 + 46.
Show a hint
Write 46 as zero hundreds, four tens, six ones.
Reveal answer and explanation
358
300 + 50 + 8 = 358.
Practice 2
Why is lining up 46 under the hundreds in 312 wrong?
Show a hint
The digits would represent different units.
Reveal answer and explanation
It would treat 46 as 460
The ones digits must align so units are added to matching units.
Take the idea with you
Combine two inventory lists by adding matching units in columns.
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: Trade ten ones when adding
Completion is your own study record, not a test score. It stays in this browser, does not sync to another device, and can be removed by clearing browser data.