NCERT Class 2 Maths (Joyful Mathematics) · Chapter 6
Decoration for Festival
Adding and subtracting 2-digit numbers with garlands, ginladi, number lines, blocks, and the column method.
📌 What you’ll learn in this chapter
- Adding tens with tens and ones with ones
- Adding on a number line (jumps of 10, then 1s)
- Carrying: 10 ones make 1 ten
- Taking away 2-digit numbers, including borrowing a ten
- Fact families and solving word problems
🪔 Let’s Begin: Diwali Lights
Priya’s family is lighting diyas. Priya lights 24 and her cousin lights 15. How many in all?
Tens: 2 + 1 = 3 tens. Ones: 4 + 5 = 9 ones. So 3 tens and 9 ones = 39 diyas! 🪔
➕ Part 1: Adding Tens and Ones
A garland has 10 flowers. 3 garlands and 4 loose flowers = 34 flowers.
| Tens | Ones | |
|---|---|---|
| 32 | 3 | 2 |
| + 45 | 4 | 5 |
| = 77 | 7 | 7 |
💡 Number line trick
For 32 + 25: start at 32, jump 10 (42), jump 10 (52), then 5 small steps (57). So 32 + 25 = 57.
🔄 Part 2: When Ones Make a Ten (Carrying)
27 + 18: ones 7 + 8 = 15 = 1 ten and 5 ones. Carry the 1 ten.
Tens: 2 + 1 + 1 (carried) = 4. Answer: 45.
⚠️ Common mistake
Writing 27 + 18 = 315 (putting 15 under the ones). ❌ Only 5 goes in the ones place. The 1 ten is carried to the tens place.
➖ Part 3: Taking Away
Easy case, 58 − 23: ones 8 − 3 = 5, tens 5 − 2 = 3, so 35.
Borrowing, 42 − 17: we can’t take 7 from 2! Break 1 ten into 10 ones: 12 − 7 = 5. The tens are now 3, and 3 − 1 = 2. Answer: 25.
⚠️ Common mistake
Doing 42 − 17 as “7 − 2 = 5” and writing 35. ❌ Always take the bottom number away from the top. If the top ones digit is smaller, borrow a ten.
💡 Check your subtraction
42 − 17 = 25? Check: 25 + 17 = 42 ✔️. Adding back always tells you if you’re right.
👨👩👧👦 Part 4: Fact Families
With 30, 40, and 70: 30 + 40 = 70 · 40 + 30 = 70 · 70 − 40 = 30 · 70 − 30 = 40
✏️ Practice Time
Try these on your own first, then check your answer below each question.
Q1. 41 + 36 = ?
✅ Answer77
Q2. 38 + 27 = ?
✅ AnswerOnes 8 + 7 = 15, write 5 and carry 1. Tens 3 + 2 + 1 = 6. 65
Q3. 69 − 34 = ?
✅ Answer35
Q4. 53 − 28 = ?
✅ AnswerBorrow: 13 − 8 = 5, and 4 − 2 = 2. 25
Q5. Aman had ₹60 and spent ₹35. How much is left?
✅ Answer60 − 35 = ₹25
📘 NCERT Textbook Activity Help
Hints and answers for the activities in the textbook, page by page. Try each one yourself before looking at the answer!
Pages 50–52 · GarlandsFlowers table and pairs
✅ AnswerEach garland has 10 flowers. Rohan 1 garland + 2 = 12 · Simran 3 + 7 = 37 · Akash 4 + 8 = 48 · Suwali 5 garlands + 3 flowers = 53 · Zoha 2 + 0 = 20 · Javed 4 + 3 = 43
Rohan + Suwali = 65 · Zoha + Javed = 63 · Zoha + Akash = 68 · Rohan + Simran = 49
Pages 53–55 · Ginladi and number lineRohan + Suwali = 65 · Zoha + Javed = 63 · Zoha + Akash = 68 · Rohan + Simran = 49
Add
✅ Answer25 + 12 = 37 · 57 + 34 = 91 · 24 + 43 = 67 · 23 + 14 = 37
24 + 16 = 40 · 11 + 22 = 33 · 22 + 16 = 38 · 18 + 13 = 31
Number line box with jumps +10, +10, +3 from 11: 11 + 23 = 34 (check the start number in your book).
44 + 23 = 67 · 56 + 23 = 79 · 60 + 25 = 85 · 52 + 30 = 82
Pages 56–58 · Adding with blocks24 + 16 = 40 · 11 + 22 = 33 · 22 + 16 = 38 · 18 + 13 = 31
Number line box with jumps +10, +10, +3 from 11: 11 + 23 = 34 (check the start number in your book).
44 + 23 = 67 · 56 + 23 = 79 · 60 + 25 = 85 · 52 + 30 = 82
Tens and ones blocks
✅ Answer23 + 38 = 61 · 36 + 47 = 83 (worked in the book)
45 + 49 = 94 · 58 + 32 = 90 · 80 + 14 = 94 · 26 + 48 = 74
46 + 39 = 85 · 56 + 19 = 75 · 36 + 8 = 44 · 30 + 58 = 88 · 45 + 35 = 80
Page 59 · Word problems (adding)45 + 49 = 94 · 58 + 32 = 90 · 80 + 14 = 94 · 26 + 48 = 74
46 + 39 = 85 · 56 + 19 = 75 · 36 + 8 = 44 · 30 + 58 = 88 · 45 + 35 = 80
Solve
✅ AnswerRuns: 43 + 58 = 101 · Pencils: 12 + 36 = 48 · Marbles: 34 + 57 = 91 · Money: 56 + 35 = ₹91 · People: 36 + 47 = 83
Pages 60–62 · Taking awayDiyas, ginladi, and number line
✅ AnswerDiyas: 75 − 35 = 40 · 32 − 12 = 20
Ginladi: 18 − 9 = 9 · 12 − 8 = 4 · 30 − 18 = 12 · 23 − 14 = 9 · 26 − 17 = 9
Number line: 19 − 15 = 4 (example) · 39 − 28 = 11 · 38 − 11 = 27 · 22 − 22 = 0 · 14 − 0 = 14 · 35 − 12 = 23. For the boxes that show only jumps, count the jumps back from the start number.
Pages 63–66 · Column subtractionGinladi: 18 − 9 = 9 · 12 − 8 = 4 · 30 − 18 = 12 · 23 − 14 = 9 · 26 − 17 = 9
Number line: 19 − 15 = 4 (example) · 39 − 28 = 11 · 38 − 11 = 27 · 22 − 22 = 0 · 14 − 0 = 14 · 35 − 12 = 23. For the boxes that show only jumps, count the jumps back from the start number.
Subtract
✅ Answer45 − 12 = 33 · 37 − 24 = 13 · 24 − 13 = 11 · 54 − 31 = 23 · 32 − 12 = 20 · 46 − 34 = 12
Money: Shikha 82 − 22 = ₹60 · Ruby 60 − 20 = ₹40
Jyoti’s flowers: 46 − 18 = 28 · 28 − 5 = 23 · 54 − 28 = 26 · 73 − 47 = 26
45 − 18 = 27 · 84 − 37 = 47 · 65 − 45 = 20 · 27 − 27 = 0 · 93 − 48 = 45
Skip the rope: Aman 20 − 14 = 6 more · Avni 20 − 12 = 8 more
Page 67 · Word problems (taking away)Money: Shikha 82 − 22 = ₹60 · Ruby 60 − 20 = ₹40
Jyoti’s flowers: 46 − 18 = 28 · 28 − 5 = 23 · 54 − 28 = 26 · 73 − 47 = 26
45 − 18 = 27 · 84 − 37 = 47 · 65 − 45 = 20 · 27 − 27 = 0 · 93 − 48 = 45
Skip the rope: Aman 20 − 14 = 6 more · Avni 20 − 12 = 8 more
Solve
✅ AnswerShells: 63 − 26 = 37 · Bus: 54 − 16 = 38 · Balloons: 40 − 13 = 27 · Bangles: 72 − 36 = 36 · Birds: 87 − 56 = 31 · Dribbles: 35 − 18 = 17
Pages 68–70 · Fact families and puzzlesFamilies, pyramids, and rings
✅ Answer20, 30, 50: 20 + 30 = 50 · 30 + 20 = 50 · 50 − 30 = 20 · 50 − 20 = 30
10, 20, 30: 10 + 20 = 30 · 20 + 10 = 30 · 30 − 20 = 10 · 30 − 10 = 20
20, 80, 100: 80 + 20 = 100 · 20 + 80 = 100 · 100 − 20 = 80 · 100 − 80 = 20
Addition pyramid (5, 3, 6, 8): 8, 9, 14 → 17, 23 → top 40
Addition pyramid (6, 4, 3, 8): 10, 7, 11 → 17, 18 → top 35
Subtraction pyramids: each box = the bigger number minus the smaller number of the two boxes below it. If a lower box is missing, work backwards: missing number = upper box + the other lower number (or the other lower number − upper box).
Rings: each number on a side is the sum of the two corner numbers next to it.
Page 71 · Shopping and checking10, 20, 30: 10 + 20 = 30 · 20 + 10 = 30 · 30 − 20 = 10 · 30 − 10 = 20
20, 80, 100: 80 + 20 = 100 · 20 + 80 = 100 · 100 − 20 = 80 · 100 − 80 = 20
Addition pyramid (5, 3, 6, 8): 8, 9, 14 → 17, 23 → top 40
Addition pyramid (6, 4, 3, 8): 10, 7, 11 → 17, 18 → top 35
Subtraction pyramids: each box = the bigger number minus the smaller number of the two boxes below it. If a lower box is missing, work backwards: missing number = upper box + the other lower number (or the other lower number − upper box).
Rings: each number on a side is the sum of the two corner numbers next to it.
Hania, Mansi, and Daljeet
✅ AnswerThey spent 24 + 37 = ₹61, so ₹78 − 61 = ₹17 is left.
Daljeet’s mistakes: 25 + 36 = 61 (not 511, he forgot to carry) · 37 + 58 = 95 (not 131) · 35 − 17 = 18 (not 22, he took the smaller ones digit from the bigger one) · 57 − 78: you can’t take a bigger number from a smaller one here, so it should be 78 − 57 = 21 · 30 − 17 = 13 (not 27)
Daljeet’s mistakes: 25 + 36 = 61 (not 511, he forgot to carry) · 37 + 58 = 95 (not 131) · 35 − 17 = 18 (not 22, he took the smaller ones digit from the bigger one) · 57 − 78: you can’t take a bigger number from a smaller one here, so it should be 78 − 57 = 21 · 30 − 17 = 13 (not 27)
👨👩👧 Tips for Parents
- Use bundles of 10 sticks and loose sticks to show carrying and borrowing.
- While shopping, ask: “We had ₹50 and spent ₹23. What’s left?”
- Ask your child to check each subtraction by adding back.