Chapter 14 of 15
Chapter 14: Birds Come, Birds Go
Token Cards, Migratory Birds, Bus Passengers & Cricket Century | CBSE Session 2026–27
Core Pedagogical Competencies & Concepts
- Using token cards [10] (yellow square) and [1] (blue triangle) for mental operations.
- Solving addition when new birds fly into a lake flock.
- Solving subtraction when groups of birds fly away.
- Cricket score calculation: finding how many runs needed to complete 100 runs (a century).
All Textbook Exercises & In-Text Tasks (18 Questions)
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Q1
Textbook Exercise • Token Card Representation
In the Flute Man counting method, draw or describe the token cards for 34 birds. (Square [10] = 10, Triangle [1] = 1).
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• In 34, there are 3 tens and 4 ones.
• Flute Man uses: Three [10] cards and four [1] cards.
• In 34, there are 3 tens and 4 ones.
• Flute Man uses: Three [10] cards and four [1] cards.
CBSE Step-by-Step Marking Scheme
3 cards of [10] identified
1 M
4 cards of [1] identified
1 M
Q2
Textbook Exercise • New Birds Arriving
There were 16 birds sitting on a tree branch. A flock of 25 more birds arrived. How many birds are there now?
[3 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Initial birds = 16 (1 ten and 6 ones)
• Arrived birds = 25 (2 tens and 5 ones)
• Add ones: 6 + 5 = 11 ones (Regroup 10 ones into 1 ten, leaving 1 one).
• Add tens: 1 + 2 + 1 = 4 tens.
• Total = 40 + 1 = 41 birds.
• Initial birds = 16 (1 ten and 6 ones)
• Arrived birds = 25 (2 tens and 5 ones)
• Add ones: 6 + 5 = 11 ones (Regroup 10 ones into 1 ten, leaving 1 one).
• Add tens: 1 + 2 + 1 = 4 tens.
• Total = 40 + 1 = 41 birds.
CBSE Step-by-Step Marking Scheme
Ones addition and regrouping shown
1 M
Tens addition shown
1 M
Final sum 41 birds correct
1 M
Q3
Textbook Exercise • Birds Flying Away
There were 35 birds on a lake. In the evening, 17 birds flew away. How many birds were left?
[3 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Total birds = 35 (3 tens and 5 ones)
• Flew away = 17 (1 ten and 7 ones)
• 5 is smaller than 7, so borrow 1 ten (leaving 2 tens). 5 becomes 15 ones.
• Ones: 15 - 7 = 8.
• Tens: 2 - 1 = 1.
• Remaining birds = 18 birds.
• Total birds = 35 (3 tens and 5 ones)
• Flew away = 17 (1 ten and 7 ones)
• 5 is smaller than 7, so borrow 1 ten (leaving 2 tens). 5 becomes 15 ones.
• Ones: 15 - 7 = 8.
• Tens: 2 - 1 = 1.
• Remaining birds = 18 birds.
CBSE Step-by-Step Marking Scheme
Borrowing step shown (15 - 7 = 8)
1 M
Tens subtraction (2 - 1 = 1)
1 M
18 birds remaining correct
1 M
Q4
Cricket Score • Century Calculation
In a cricket match, Rahul is batting on 78 runs. How many more runs does he need to complete a century (100 runs)?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Target = 100 runs (Century)
• Current score = 78 runs
• Runs needed = 100 - 78 = 100 - 70 - 8 = 30 - 8 = 22 runs.
• Target = 100 runs (Century)
• Current score = 78 runs
• Runs needed = 100 - 78 = 100 - 70 - 8 = 30 - 8 = 22 runs.
CBSE Step-by-Step Marking Scheme
100 - 78 subtraction shown
1 M
22 runs correct
1 M
Q5
Cricket Score • Half Century Check
Rohit scored 46 runs. Did he complete a half-century (50 runs)? How many runs was he short by?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Half-century = 50 runs.
• Rohit's score = 46 runs.
• Since 46 < 50, he did not complete a half-century.
• Shortage = 50 - 46 = 4 runs short.
• Half-century = 50 runs.
• Rohit's score = 46 runs.
• Since 46 < 50, he did not complete a half-century.
• Shortage = 50 - 46 = 4 runs short.
CBSE Step-by-Step Marking Scheme
Negative confirmation (did not complete)
1 M
Shortage of 4 runs calculated
1 M
Q6
Bus Passengers Word Problem
A bus had 48 passengers. At the red light, 19 passengers got down. How many passengers remained in the bus?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Total passengers = 48
• Passengers got down = 19
• Remaining = 48 - 19 = 48 - 20 + 1 = 28 + 1 = 29 passengers.
• Total passengers = 48
• Passengers got down = 19
• Remaining = 48 - 19 = 48 - 20 + 1 = 28 + 1 = 29 passengers.
CBSE Step-by-Step Marking Scheme
48 - 19 shown
1 M
29 passengers correct
1 M
Q7
Token Card Addition
Solve using token cards: 28 + 14 = ___ tens + ___ ones.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 28 = 2 tens + 8 ones
• 14 = 1 ten + 4 ones
• Ones: 8 + 4 = 12 ones = 1 ten + 2 ones.
• Tens: 2 + 1 + 1 = 4 tens.
• Total = 4 tens + 2 ones = 42.
• 28 = 2 tens + 8 ones
• 14 = 1 ten + 4 ones
• Ones: 8 + 4 = 12 ones = 1 ten + 2 ones.
• Tens: 2 + 1 + 1 = 4 tens.
• Total = 4 tens + 2 ones = 42.
CBSE Step-by-Step Marking Scheme
Regrouping step shown
1 M
Final answer 42 correct
1 M
Q8
Word Problem • Garden Roses
A rose bush has 34 red roses and 29 yellow roses. How many roses are on the bush altogether?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Red roses = 34
• Yellow roses = 29
• Total roses = 34 + 29 = 34 + 30 - 1 = 64 - 1 = 63 roses.
• Red roses = 34
• Yellow roses = 29
• Total roses = 34 + 29 = 34 + 30 - 1 = 64 - 1 = 63 roses.
CBSE Step-by-Step Marking Scheme
Addition 34 + 29 shown
1 M
63 roses correct
1 M
Q9
Pencil Packets Word Problem
A school store has 72 pencils. If they distribute 38 pencils to Class 2 students, how many pencils are left in the store?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Total pencils = 72
• Pencils distributed = 38
• Pencils left = 72 - 38 = 72 - 40 + 2 = 32 + 2 = 34 pencils.
• Total pencils = 72
• Pencils distributed = 38
• Pencils left = 72 - 38 = 72 - 40 + 2 = 32 + 2 = 34 pencils.
CBSE Step-by-Step Marking Scheme
Subtraction 72 - 38 shown
1 M
34 pencils left correct
1 M
Q10
Mental Math • Near Tens Strategy
Subtract 19 from 53 using mental math. Explain your thought process.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Explanation:
• 19 is 1 less than 20.
• First subtract 20: 53 - 20 = 33.
• Since we subtracted 1 extra, add 1 back: 33 + 1 = 34.
• 19 is 1 less than 20.
• First subtract 20: 53 - 20 = 33.
• Since we subtracted 1 extra, add 1 back: 33 + 1 = 34.
CBSE Step-by-Step Marking Scheme
Near-tens mental strategy explained
1 M
34 correct answer
1 M
Q11
Comparative Problem • Bird Watcher
Pooja spotted 27 pigeons and 19 parrots in the city garden. How many more pigeons did she see than parrots?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Pigeons = 27
• Parrots = 19
• Difference = 27 - 19 = 8 more pigeons.
• Pigeons = 27
• Parrots = 19
• Difference = 27 - 19 = 8 more pigeons.
CBSE Step-by-Step Marking Scheme
Subtraction 27 - 19 shown
1 M
8 pigeons difference correct
1 M
Q12
Token Card Subtraction
If you have five [10] cards and three [1] cards (53), and you cross out two [10] cards and eight [1] cards (28), what cards are left?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Need to take 8 ones from 3 ones: exchange one [10] card for ten [1] cards.
• Now you have four [10] cards and thirteen [1] cards.
• Remove eight [1] cards: 13 - 8 = five [1] cards left.
• Remove two [10] cards: 4 - 2 = two [10] cards left.
• Value remaining = (2 × 10) + 5 = 25.
• Need to take 8 ones from 3 ones: exchange one [10] card for ten [1] cards.
• Now you have four [10] cards and thirteen [1] cards.
• Remove eight [1] cards: 13 - 8 = five [1] cards left.
• Remove two [10] cards: 4 - 2 = two [10] cards left.
• Value remaining = (2 × 10) + 5 = 25.
CBSE Step-by-Step Marking Scheme
Exchange of [10] card for ten [1] cards shown
1 M
Result 25 verified
1 M
Q13
True or False
State True or False:
(a) In cricket, 1 century = 100 runs.
(b) 60 - 25 = 45.
[2 Marks]
(a) In cricket, 1 century = 100 runs.
(b) 60 - 25 = 45.
✅ Step-by-Step Solution & Working
Answers:
(a) True. A century is exactly 100 runs.
(b) False. 60 - 25 = 35 (not 45).
(a) True. A century is exactly 100 runs.
(b) False. 60 - 25 = 35 (not 45).
CBSE Step-by-Step Marking Scheme
(a) True
1 M
(b) False with 35
1 M
Q14
Chapter Reflection
How does the story 'Birds Come, Birds Go' help us understand real-world math?
[2 Marks]
✅ Step-by-Step Solution & Working
Summary:
• Real populations (like birds, passengers, or sports scores) constantly increase (birds arrive/add) and decrease (birds leave/subtract).
• Using token cards allows us to handle 2-digit regrouping visually before doing abstract paper arithmetic.
• Real populations (like birds, passengers, or sports scores) constantly increase (birds arrive/add) and decrease (birds leave/subtract).
• Using token cards allows us to handle 2-digit regrouping visually before doing abstract paper arithmetic.
CBSE Step-by-Step Marking Scheme
Addition and subtraction dynamics explained
1 M
Visual token card utility explained
1 M
Q15
Quick Quiz Problem
What is 85 - 35?
[1 Marks]
✅ Step-by-Step Solution & Working
Calculation:
• 85 - 30 = 55
• 55 - 5 = 50.
• 85 - 30 = 55
• 55 - 5 = 50.
CBSE Step-by-Step Marking Scheme
50 correct
1 M
Q16
Textbook Story • Tree Tokens
There were 25 birds on a tree. In the morning, 16 more birds flew in. How many birds are there on the tree now? Solve using 10s and 1s tokens.
[2.5 Marks]
✅ Step-by-Step Solution & Working
Calculation:
• 25 = 2 tens + 5 ones.
• 16 = 1 ten + 6 ones.
• Add ones: 5 + 6 = 11 ones (1 ten + 1 one).
• Add tens: 2 + 1 + 1 = 4 tens.
• Total = 41 birds on the tree.
• 25 = 2 tens + 5 ones.
• 16 = 1 ten + 6 ones.
• Add ones: 5 + 6 = 11 ones (1 ten + 1 one).
• Add tens: 2 + 1 + 1 = 4 tens.
• Total = 41 birds on the tree.
CBSE Step-by-Step Marking Scheme
Token regrouping method
1 M
Final count: 41 birds
1.5 M
Q17
Textbook Problem • Bus Passengers
A school bus had 35 children. At the first stop, 12 children got down. How many children are still in the bus?
[2 Marks]
✅ Step-by-Step Solution & Working
Calculation:
• Initial children = 35
• Children who got down = 12
• Remaining children = 35 - 12 = 23 children.
• Initial children = 35
• Children who got down = 12
• Remaining children = 35 - 12 = 23 children.
CBSE Step-by-Step Marking Scheme
Subtraction 35 - 12
1 M
23 children remaining
1 M
Q18
Mental Math • Regrouping Challenge
Subtract 18 from 42 using expanded form.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 42 = 30 + 12 (borrowing 10).
• 18 = 10 + 8.
• (12 - 8) + (30 - 10) = 4 + 20 = 24.
• 42 = 30 + 12 (borrowing 10).
• 18 = 10 + 8.
• (12 - 8) + (30 - 10) = 4 + 20 = 24.
CBSE Step-by-Step Marking Scheme
Borrowing/regrouping step
1 M
Answer: 24
1 M
🌟 NEP 2020 Competency-Based Case Study
Sultanpur Lake Bird Sanctuary Census
During winter, migratory swans, cranes, and storks fly to the lake. In the morning, children count 25 swans and 18 cranes. By late afternoon, 12 swans fly away to feed in nearby fields, while 7 new cranes arrive.
Analytical Task: How many total birds were at the lake in the morning? How many swans remained after 12 flew away? How many cranes were there after 7 new ones arrived?
Evaluation & Model Answer:
1. Morning total: 25 + 18 = 43 birds.
2. Remaining swans: 25 - 12 = 13 swans.
3. Cranes count: 18 + 7 = 25 cranes.
4. Late afternoon total: 13 swans + 25 cranes = 38 birds.
2. Remaining swans: 25 - 12 = 13 swans.
3. Cranes count: 18 + 7 = 25 cranes.
4. Late afternoon total: 13 swans + 25 cranes = 38 birds.
Rubric: 1 M for morning total (43) + 1 M for remaining swans (13) + 1 M for updated cranes (25)