Class 2 · Mathematics
Addition and subtraction
📘 Chapter notes
The key ideas of this chapter, answered through the six guiding questions. Read them with your textbook.
1What am I looking at?
Answer: Adding and subtracting numbers, with and without regrouping.
2What are its main parts or ideas?
Answer: Addends and sum in addition; minuend, subtrahend and difference in subtraction.
3How does it work?
Answer: Write numbers in columns by place value and work from the ones column; carry a ten or borrow a ten when needed.
4Why is it important?
Answer: Used for shopping, scores, distances and keeping count.
5What happens if something changes?
Answer: Addition and subtraction undo each other: if 35 + 18 = 53, then 53 − 18 = 35.
6What should I remember for the exam?
Answer: Solve column sums, word problems and check subtraction by adding.
📗 Full lesson: Addition and subtraction
This topic comes from GayaGnan's India-wide K–12 catalog. It is not copied from, or an official chapter of, any board's textbook: check your board's syllabus for the exact chapter and depth. Open as its own page →
🧊 3D / visual
🧊 3D
ℹ️ Blocks are a model of numbers, not real objects.
🎯 Learning outcomes
- Add and subtract numbers up to 99 without and with regrouping
- Choose addition or subtraction for a word problem
- Check a subtraction with addition
Before you start: Counting forward and backward; tens and ones.
📖 Explanation
Addition puts groups together. 23 + 14 means 2 tens + 1 ten = 3 tens and 3 ones + 4 ones = 7 ones, so the sum is 37.
When the ones add up to 10 or more, we make a new ten (regrouping or carrying): 28 + 5 = 33 because 8 + 5 = 13 ones = 1 ten and 3 ones.
Subtraction takes away or finds the difference. If there are not enough ones, we break one ten into 10 ones (borrowing): 42 − 7 = 35. We can check: 35 + 7 = 42.
A school bus in Pune picks up 26 children and then 15 more. 26 + 15 = 41 children are on the bus.
✗ In 42 − 17 you can take 2 from 7
✓ Always subtract the bottom ones from the top ones; if the top is smaller, regroup a ten: 12 − 7 = 5 ones, 3 − 1 = 2 tens, so 25.
🧪 Try this activity
Play shopkeeper with paper coins of ₹1 and ₹10. Buy two items and add the prices, then pay ₹50 and count the change.
✍️ Question bank with answers
Tap an option to check multiple-choice answers. Open “Answer” or “Marking points” for the others.
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What is 36 + 27?
Answer
A. 63
6 + 7 = 13 ones = 1 ten 3 ones; 3 + 2 + 1 = 6 tens; so 63.
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What is 50 − 18?
Answer
B. 32
Break 1 ten: 10 − 8 = 2 ones, 4 − 1 = 3 tens, so 32. Check: 32 + 18 = 50.
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Which sum is 20?
Answer
A. 12 + 8
12 + 8 = 20; the others are 19, 21 and 19.
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45 + 0 = ?
Answer
45
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70 − 30 = ?
Answer
40
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Find 64 − 29 and check your answer.
Marking points
- 14 − 9 = 5 ones after regrouping, 5 − 2 = 3 tens, so 35
- Check: 35 + 29 = 64
-
A farmer had 58 mangoes. He sold 24 and then picked 13 more. How many mangoes does he have now?
Marking points
- Sold: 58 − 24 = 34
- Picked: 34 + 13 = 47
- He has 47 mangoes
-
A pencil costs ₹15 and an eraser ₹8. How much change from ₹50?
Answer
- Total 15 + 8 = ₹23
- Change 50 − 23 = ₹27
-
Ravi read 38 pages on Monday and 45 on Tuesday. How many pages did he read?
Answer
- 8 + 5 = 13 ones, write 3, carry 1 ten
- 3 + 4 + 1 = 8 tens
- 83 pages
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