Chapter 8 of 13
Chapter 8: Numbers from Twenty-one to Fifty
Bundles of 10 and Loose Units, 21-50 Strips & Number Grids | CBSE Session 2026–27
Core Pedagogical Competencies & Concepts
- Counting from 21 to 50 using bundles of 10 and loose sticks.
- Writing numerals and number names from Twenty-one to Fifty.
- Filling missing numbers in sequences and number strips.
- Identifying Tens and Ones digits.
All Textbook Exercises & In-Text Tasks (22 Questions)
100% Complete Ingestion
Q1
Textbook Exercise • 2 Bundles and 5 Sticks
Look at the picture: 2 bundles of 10 matchsticks and 5 loose matchsticks. What number is this?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 2 bundles = 20
• 5 loose sticks = 5
• Total = 20 + 5 = 25 (Twenty-five).
• 2 bundles = 20
• 5 loose sticks = 5
• Total = 20 + 5 = 25 (Twenty-five).
CBSE Step-by-Step Marking Scheme
20 + 5 = 25
1 M
Number name Twenty-five
1 M
Q2
Textbook Exercise • 3 Bundles and 3 Sticks
Write the number for 3 bundles of 10 and 3 loose sticks.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 3 tens + 3 ones = 30 + 3 = 33 (Thirty-three).
• 3 tens + 3 ones = 30 + 3 = 33 (Thirty-three).
CBSE Step-by-Step Marking Scheme
33 (Thirty-three)
2 M
Q3
Textbook Exercise • 4 Bundles and 0 Sticks
Write the number for 4 bundles of 10 and 0 loose sticks.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 4 tens + 0 ones = 40 (Forty).
• 4 tens + 0 ones = 40 (Forty).
CBSE Step-by-Step Marking Scheme
40 (Forty)
2 M
Q4
Textbook Exercise • 4 Bundles and 9 Sticks
Write the number for 4 bundles of 10 and 9 loose sticks.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 4 tens + 9 ones = 40 + 9 = 49 (Forty-nine).
• 4 tens + 9 ones = 40 + 9 = 49 (Forty-nine).
CBSE Step-by-Step Marking Scheme
49 (Forty-nine)
2 M
Q5
Textbook Exercise • 5 Bundles of 10
What number is represented by 5 full bundles of 10 matchsticks?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 5 tens = 50 (Fifty).
• 5 tens = 50 (Fifty).
CBSE Step-by-Step Marking Scheme
50 (Fifty)
2 M
Q6
Textbook Exercise • Missing Numbers 21 to 30
Fill the missing numbers: 21, __, 23, 24, __, 26, __, 28, 29, 30.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Missing numbers: 22, 25, 27.
• Missing numbers: 22, 25, 27.
CBSE Step-by-Step Marking Scheme
Filled 22, 25, 27
2 M
Q7
Textbook Exercise • Missing Numbers 31 to 40
Fill the missing numbers: 31, 32, __, 34, 35, __, 37, __, 39, 40.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Missing numbers: 33, 36, 38.
• Missing numbers: 33, 36, 38.
CBSE Step-by-Step Marking Scheme
Filled 33, 36, 38
2 M
Q8
Textbook Exercise • Missing Numbers 41 to 50
Fill the missing numbers: 41, __, 43, __, 45, 46, __, 48, 49, 50.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Missing numbers: 42, 44, 47.
• Missing numbers: 42, 44, 47.
CBSE Step-by-Step Marking Scheme
Filled 42, 44, 47
2 M
Q9
Textbook Exercise • Tens and Ones for 28
Break 28 into Tens and Ones.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 28 = 2 Tens and 8 Ones.
• 28 = 2 Tens and 8 Ones.
CBSE Step-by-Step Marking Scheme
2 Tens and 8 Ones
2 M
Q10
Textbook Exercise • Tens and Ones for 45
Break 45 into Tens and Ones.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 45 = 4 Tens and 5 Ones.
• 45 = 4 Tens and 5 Ones.
CBSE Step-by-Step Marking Scheme
4 Tens and 5 Ones
2 M
Q11
Textbook Exercise • What Number Has 3 Tens and 6 Ones?
Write the numeral for: 3 Tens and 6 Ones.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 30 + 6 = 36.
• 30 + 6 = 36.
CBSE Step-by-Step Marking Scheme
36
2 M
Q12
Textbook Exercise • What Number Has 4 Tens and 2 Ones?
Write the numeral for: 4 Tens and 2 Ones.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 40 + 2 = 42.
• 40 + 2 = 42.
CBSE Step-by-Step Marking Scheme
42
2 M
Q13
Textbook Exercise • Number Names 21 to 25
Write number names for: 21, 22, 23, 24, 25.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 21 = Twenty-one
• 22 = Twenty-two
• 23 = Twenty-three
• 24 = Twenty-four
• 25 = Twenty-five
• 21 = Twenty-one
• 22 = Twenty-two
• 23 = Twenty-three
• 24 = Twenty-four
• 25 = Twenty-five
CBSE Step-by-Step Marking Scheme
All 5 spelled correctly
2 M
Q14
Textbook Exercise • Number Names 30, 40, 50
Write the spellings for: 30, 40, 50.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 30 = Thirty
• 40 = Forty
• 50 = Fifty
• 30 = Thirty
• 40 = Forty
• 50 = Fifty
CBSE Step-by-Step Marking Scheme
Thirty, Forty, Fifty
2 M
Q15
Textbook Exercise • What Comes Just After 29?
What number comes just after 29? What number comes just after 39?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Just after 29 is 30.
• Just after 39 is 40.
• Just after 29 is 30.
• Just after 39 is 40.
CBSE Step-by-Step Marking Scheme
After 29 = 30
1 M
After 39 = 40
1 M
Q16
Textbook Exercise • What Comes Just Before 50?
What number comes just before 50?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 50 - 1 = 49.
• 50 - 1 = 49.
CBSE Step-by-Step Marking Scheme
49
2 M
Q17
Textbook Exercise • Between 35 and 37
What number is between 35 and 37?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• The number is 36.
• The number is 36.
CBSE Step-by-Step Marking Scheme
36
2 M
Q18
Textbook Exercise • Circle Greater Number
Circle the greater number in each pair: (a) 26 and 32, (b) 48 and 41.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• (a) 3 tens > 2 tens → 32 is greater.
• (b) Same tens (4), but 8 ones > 1 one → 48 is greater.
• (a) 3 tens > 2 tens → 32 is greater.
• (b) Same tens (4), but 8 ones > 1 one → 48 is greater.
CBSE Step-by-Step Marking Scheme
32 circled
1 M
48 circled
1 M
Q19
Word Problem • Flowers for Teacher's Day
Students made 3 garlands of 10 roses each and had 5 loose roses. How many roses in total?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 30 + 5 = 35 roses.
• 30 + 5 = 35 roses.
CBSE Step-by-Step Marking Scheme
30 + 5 = 35 roses
2 M
Q20
Activity • Match Numeral to Picture
Match: 2 bundles and 9 sticks → 29; 4 bundles and 7 sticks → 47.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 20 + 9 = 29
• 40 + 7 = 47
• 20 + 9 = 29
• 40 + 7 = 47
CBSE Step-by-Step Marking Scheme
Matches verified
2 M
Q21
Mental Math • How Many Tens in 50?
How many tens make 50?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 10 + 10 + 10 + 10 + 10 = 50.
• Exactly 5 tens make 50.
• 10 + 10 + 10 + 10 + 10 = 50.
• Exactly 5 tens make 50.
CBSE Step-by-Step Marking Scheme
5 tens
2 M
Q22
Competency Review • Skip Counting by 5s to 50
Write the skip-counting chain by 5s from 25 to 50: 25, 30, __, __, __, 50.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• 25, 30, 35, 40, 45, 50.
• 25, 30, 35, 40, 45, 50.
CBSE Step-by-Step Marking Scheme
35, 40, 45
2 M
🌟 NEP 2020 Competency-Based Case Study
Sugarcane Bundles Case Study
Farmer Ramu ties harvested sugarcane stalks into bundles of 10 stalks each. He has 3 full bundles and 7 loose stalks.
Analytical Task: What total number of sugarcane stalks does Farmer Ramu have? Write the number in expanded form.
Evaluation & Model Answer:
1. 3 bundles of 10 = 30. Loose stalks = 7.
2. Total stalks = 30 + 7 = 37 sugarcane stalks.
3. Expanded form: 30 + 7 = 3 tens and 7 ones.
2. Total stalks = 30 + 7 = 37 sugarcane stalks.
3. Expanded form: 30 + 7 = 3 tens and 7 ones.
Rubric: 1.5 M for 37 stalks + 1.5 M for expanded form (30 + 7)