Chapter 4 of 14
Chapter 4: Tick-Tick-Tick
Clock Reading, Movement of Minute Hand, 12h vs 24h Formats & Expiry Date Verification | CBSE Session 2026–27
Core Pedagogical Competencies & Concepts
- Understanding clock mechanics: the minute hand moves 1 small mark (6°) in 1 minute, 5 marks (30°) from one number to the next.
- Calculating the time taken by the minute hand to move from one digit to another.
- Differentiating morning (am) and afternoon/evening (pm).
- Reading manufacturing (MFG) and expiry dates on ghee tins, medicines, and butter packets.
All Textbook Exercises & In-Text Tasks (15 Questions)
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Q1
Minute Hand Movement
How many minutes does it take the minute hand to move from: (a) 2 to 7, (b) 12 to 8, (c) 1 to 4, (d) 7 to 10?
[3 Marks]
✅ Step-by-Step Solution & Working
Each number on the clock represents 5 minutes.
• (a) From 2 to 7: (7 - 2) = 5 numbers. 5 × 5 = 25 minutes.
• (b) From 12 to 8: 8 numbers forward. 8 × 5 = 40 minutes.
• (c) From 1 to 4: (4 - 1) = 3 numbers. 3 × 5 = 15 minutes.
• (d) From 7 to 10: (10 - 7) = 3 numbers. 3 × 5 = 15 minutes.
• (a) From 2 to 7: (7 - 2) = 5 numbers. 5 × 5 = 25 minutes.
• (b) From 12 to 8: 8 numbers forward. 8 × 5 = 40 minutes.
• (c) From 1 to 4: (4 - 1) = 3 numbers. 3 × 5 = 15 minutes.
• (d) From 7 to 10: (10 - 7) = 3 numbers. 3 × 5 = 15 minutes.
CBSE Step-by-Step Marking Scheme
Correct answers for (a) and (b)
1.5 M
Correct answers for (c) and (d)
1.5 M
Q2
Product Expiry Date Check
Amrit bought butter on 15 May 2026. It was written on the packet 'Best before 180 days from the date of packing'. The date of packing was 15/01/2026. Should Amrit eat this butter or not? Explain your calculation.
[3 Marks]
✅ Step-by-Step Solution & Working
Step 1: Calculate days from 15 January 2026 to 15 May 2026:
• January: 31 - 15 = 16 days remaining.
• February 2026 (non-leap year) = 28 days.
• March = 31 days.
• April = 30 days.
• May (up to 15th) = 15 days.
• Total days passed = 16 + 28 + 31 + 30 + 15 = 120 days.
Step 2: Compare with expiry limit:
• The packet is safe for 180 days.
• Since 120 days < 180 days, the butter has NOT expired.
• Conclusion: Yes, Amrit can safely eat the butter.
• January: 31 - 15 = 16 days remaining.
• February 2026 (non-leap year) = 28 days.
• March = 31 days.
• April = 30 days.
• May (up to 15th) = 15 days.
• Total days passed = 16 + 28 + 31 + 30 + 15 = 120 days.
Step 2: Compare with expiry limit:
• The packet is safe for 180 days.
• Since 120 days < 180 days, the butter has NOT expired.
• Conclusion: Yes, Amrit can safely eat the butter.
CBSE Step-by-Step Marking Scheme
Accurate monthly day count sum = 120 days
2.0 M
Valid comparison and safe consumption verdict
1.0 M
Q3
Developmental Timeline • Munia's Milestones
Munia was born on 5th March 2025. She cut her first tooth on 15th September 2025 and started walking on 2nd February 2026. (a) How old was she in completed months when she cut her first tooth? (b) How many months after birth did she start walking?
[3 Marks]
✅ Step-by-Step Solution & Working
Timeline Milestones:
Date of Birth: 5th March 2025
1. (a) First Tooth (15th September 2025):
From March to September = 6 months (March 5 to Sept 5 = 6 months) + 10 days.
Munia was 6 months and 10 days old.
2. (b) Walking (2nd February 2026):
From March 2025 to January 2026 = 10 months. Adding up to Feb 2 = nearly 11 months old.
Date of Birth: 5th March 2025
1. (a) First Tooth (15th September 2025):
From March to September = 6 months (March 5 to Sept 5 = 6 months) + 10 days.
Munia was 6 months and 10 days old.
2. (b) Walking (2nd February 2026):
From March 2025 to January 2026 = 10 months. Adding up to Feb 2 = nearly 11 months old.
CBSE Step-by-Step Marking Scheme
First tooth age: 6 months 10 days
1.5 M
Walking milestone age: approx 11 months
1.5 M
Q4
Calendar Math • Number of Days in a Year
Is the year 2028 a leap year? How many days will the months of February and the entire year 2028 have?
[2 Marks]
✅ Step-by-Step Solution & Working
Leap Year Test:
A year is a leap year if its last two digits are divisible by 4.
• 28 ÷ 4 = 7 (completely divisible, remainder 0).
Therefore, 2028 is a leap year.
Days Count:
• February 2028 will have 29 days.
• The entire year 2028 will have 366 days (instead of the normal 365 days).
A year is a leap year if its last two digits are divisible by 4.
• 28 ÷ 4 = 7 (completely divisible, remainder 0).
Therefore, 2028 is a leap year.
Days Count:
• February 2028 will have 29 days.
• The entire year 2028 will have 366 days (instead of the normal 365 days).
CBSE Step-by-Step Marking Scheme
Divisibility rule proving 2028 is a leap year
1.0 M
February has 29 days and total year has 366 days
1.0 M
Q5
Building with Bricks • Brick Geometry & Measurement
A standard brick has length 20 cm, breadth 10 cm, and height 7 cm.
(a) What is the shape of a brick?
(b) What is the area of its largest face?
(c) How many bricks of 20 cm length placed end-to-end make a line 1 metre (100 cm) long?
[3 Marks]
(a) What is the shape of a brick?
(b) What is the area of its largest face?
(c) How many bricks of 20 cm length placed end-to-end make a line 1 metre (100 cm) long?
✅ Step-by-Step Solution & Working
Brick Mathematics:
• (a) Shape: A standard brick is a cuboid.
• (b) Area of largest face: Length × Breadth = 20 cm × 10 cm = 200 square centimetres (cm²).
• (c) Number of bricks in 1 m: 1 m = 100 cm. Number of bricks = 100 ÷ 20 = 5 bricks.
• (a) Shape: A standard brick is a cuboid.
• (b) Area of largest face: Length × Breadth = 20 cm × 10 cm = 200 square centimetres (cm²).
• (c) Number of bricks in 1 m: 1 m = 100 cm. Number of bricks = 100 ÷ 20 = 5 bricks.
CBSE Step-by-Step Marking Scheme
Cuboid shape
1 M
Area = 200 cm²
1 M
5 bricks
1 M
Q6
A Trip to Bhopal • Diesel Fuel Budget
During a school trip to Bhopal, 4 buses stop at a petrol pump to fill diesel. Each bus takes 50 litres of diesel. If 1 litre of diesel costs ₹70:
(a) How many litres of diesel are filled in total?
(b) What is the total bill amount the school must pay?
[3 Marks]
(a) How many litres of diesel are filled in total?
(b) What is the total bill amount the school must pay?
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• (a) Total diesel: 4 buses × 50 L = 200 litres.
• (b) Total bill amount: 200 L × ₹70/L = ₹14,000.
• (a) Total diesel: 4 buses × 50 L = 200 litres.
• (b) Total bill amount: 200 L × ₹70/L = ₹14,000.
CBSE Step-by-Step Marking Scheme
200 litres
1.5 M
₹14,000 bill
1.5 M
Q7
Long and Short • Height Comparisons
The world record for Men's High Jump is 245 cm and the Long Jump world record is 895 cm.
(a) Express the High Jump record in metres and centimetres.
(b) How many more centimetres are needed for the high jump record to reach exactly 2.5 metres (250 cm)?
[2 Marks]
(a) Express the High Jump record in metres and centimetres.
(b) How many more centimetres are needed for the high jump record to reach exactly 2.5 metres (250 cm)?
✅ Step-by-Step Solution & Working
Calculations:
• (a) High Jump: 245 cm = 2 metres 45 centimetres.
• (b) Difference: 250 cm - 245 cm = 5 centimetres.
• (a) High Jump: 245 cm = 2 metres 45 centimetres.
• (b) Difference: 250 cm - 245 cm = 5 centimetres.
CBSE Step-by-Step Marking Scheme
2 m 45 cm
1 M
5 cm difference
1 M
Q8
Tick-Tick-Tick • Expiry Dates on Food
A packet of butter shows 'Manufactured: 15/01/26' and 'Best before 180 days from manufacture'. Can it be consumed safely on 15th April 2026? Explain.
[2 Marks]
✅ Step-by-Step Solution & Working
Date Verification:
• From 15th Jan to 15th April is exactly 3 months (approx. 90 days).
• Since 90 days is well within the 180-day shelf life, the butter is completely safe to consume on 15th April 2026.
• From 15th Jan to 15th April is exactly 3 months (approx. 90 days).
• Since 90 days is well within the 180-day shelf life, the butter is completely safe to consume on 15th April 2026.
CBSE Step-by-Step Marking Scheme
Time elapsed is ~90 days
1 M
Safe to consume within 180 days
1 M
Q9
The Junk Seller • Loan and Interest
Kiran took a loan of ₹300 from a bank to set up her scrap shop. She pays back ₹51 every month for six months.
(a) How much money does she pay back in total?
(b) How much extra money (interest) did she pay to the bank?
[3 Marks]
(a) How much money does she pay back in total?
(b) How much extra money (interest) did she pay to the bank?
✅ Step-by-Step Solution & Working
Loan Repayment:
• (a) Total paid: 6 months × ₹51/month = ₹306.
• (b) Extra money (interest): ₹306 - ₹300 = ₹6.
• (a) Total paid: 6 months × ₹51/month = ₹306.
• (b) Extra money (interest): ₹306 - ₹300 = ₹6.
CBSE Step-by-Step Marking Scheme
Total repayment = ₹306
1.5 M
Interest = ₹6
1.5 M
Q10
Jugs and Mugs • Measuring Medicine Dose
A doctor prescribes a cough syrup bottle of 150 mL for a child. The child takes a 5 mL dose three times a day.
(a) How much cough syrup does the child take in one day?
(b) For how many days will the 150 mL bottle last?
[3 Marks]
(a) How much cough syrup does the child take in one day?
(b) For how many days will the 150 mL bottle last?
✅ Step-by-Step Solution & Working
Dosage Calculations:
• (a) Daily intake: 3 doses × 5 mL = 15 mL per day.
• (b) Days bottle lasts: 150 mL ÷ 15 mL/day = 10 days.
• (a) Daily intake: 3 doses × 5 mL = 15 mL per day.
• (b) Days bottle lasts: 150 mL ÷ 15 mL/day = 10 days.
CBSE Step-by-Step Marking Scheme
15 mL daily
1.5 M
Bottle lasts 10 days
1.5 M
Q11
Carts and Wheels • Circle Geometry
A cyclist has a bicycle wheel with a radius of 35 cm.
(a) What is the diameter of the wheel?
(b) What is the relationship between the radius and diameter of any circle?
[2 Marks]
(a) What is the diameter of the wheel?
(b) What is the relationship between the radius and diameter of any circle?
✅ Step-by-Step Solution & Working
Circle Properties:
• (a) Diameter: Diameter = 2 × Radius = 2 × 35 cm = 70 cm.
• (b) Relationship: The diameter is always twice the length of the radius (D = 2r), passing straight through the circle's center.
• (a) Diameter: Diameter = 2 × Radius = 2 × 35 cm = 70 cm.
• (b) Relationship: The diameter is always twice the length of the radius (D = 2r), passing straight through the circle's center.
CBSE Step-by-Step Marking Scheme
Diameter = 70 cm
1 M
Formula D = 2r stated
1 M
Q12
Halves and Quarters • Fraction Sharing
Raju has ₹100. He spends 1/2 of his money on a book, and 1/4 of his total money on a pen.
(a) How much does the book cost?
(b) How much does the pen cost?
(c) How much money does Raju have left?
[3 Marks]
(a) How much does the book cost?
(b) How much does the pen cost?
(c) How much money does Raju have left?
✅ Step-by-Step Solution & Working
Fractional Expenditure:
• (a) Book (1/2): ₹100 ÷ 2 = ₹50.
• (b) Pen (1/4): ₹100 ÷ 4 = ₹25.
• (c) Money Left: ₹100 - (₹50 + ₹25) = ₹100 - ₹75 = ₹25.
• (a) Book (1/2): ₹100 ÷ 2 = ₹50.
• (b) Pen (1/4): ₹100 ÷ 4 = ₹25.
• (c) Money Left: ₹100 - (₹50 + ₹25) = ₹100 - ₹75 = ₹25.
CBSE Step-by-Step Marking Scheme
Book = ₹50
1 M
Pen = ₹25
1 M
Remaining = ₹25
1 M
Q13
Play with Patterns • Secret Message Cipher
In a secret code, each letter is replaced by its position in the alphabet (A=1, B=2, C=3, ... Z=26).
Decode the secret message: '13 - 1 - 20 - 8 - 19'. What word does it spell?
[2 Marks]
Decode the secret message: '13 - 1 - 20 - 8 - 19'. What word does it spell?
✅ Step-by-Step Solution & Working
Decoding Cipher:
• 13 = M
• 1 = A
• 20 = T
• 8 = H
• 19 = S
The secret message spells MATHS.
• 13 = M
• 1 = A
• 20 = T
• 8 = H
• 19 = S
The secret message spells MATHS.
CBSE Step-by-Step Marking Scheme
Correct decoding to spell MATHS
2 M
Q14
Tables and Shares • Division with Remainder
A florist has 58 roses. She wants to make bouquets containing 6 roses each.
(a) How many complete bouquets can she make?
(b) How many roses will be left over?
[2 Marks]
(a) How many complete bouquets can she make?
(b) How many roses will be left over?
✅ Step-by-Step Solution & Working
Division:
• 58 ÷ 6 = 9 with a remainder of 4.
• (a) Complete bouquets: 9 bouquets (9 × 6 = 54 roses).
• (b) Leftover roses: 58 - 54 = 4 roses left over.
• 58 ÷ 6 = 9 with a remainder of 4.
• (a) Complete bouquets: 9 bouquets (9 × 6 = 54 roses).
• (b) Leftover roses: 58 - 54 = 4 roses left over.
CBSE Step-by-Step Marking Scheme
9 bouquets
1 M
4 leftover roses
1 M
Q15
Review Questions • True or False
State True or False:
(a) A square has 4 equal sides and its perimeter is 4 × side.
(b) 1 kilometre equals 100 metres.
(c) Half past 4 in the afternoon is written as 16:30 in 24-hour time.
[3 Marks]
(a) A square has 4 equal sides and its perimeter is 4 × side.
(b) 1 kilometre equals 100 metres.
(c) Half past 4 in the afternoon is written as 16:30 in 24-hour time.
✅ Step-by-Step Solution & Working
Answers:
• (a) True: Perimeter = 4 × side.
• (b) False: 1 km = 1000 metres.
• (c) True: 4:30 PM = 12:00 + 4:30 = 16:30 hours.
• (a) True: Perimeter = 4 × side.
• (b) False: 1 km = 1000 metres.
• (c) True: 4:30 PM = 12:00 + 4:30 = 16:30 hours.
CBSE Step-by-Step Marking Scheme
True, False, True with explanations
3 M
🌟 NEP 2020 Competency-Based Case Study
Missing a Train Due to 24-Hour Time Format
Ranjit has a train ticket with departure time printed as '05:30'. He reaches the railway station at 5:00 in the evening on the same day.
Analytical Task: Did Ranjit catch his train or miss it? Explain why the railway ticket printed 05:30.
Evaluation & Model Answer:
Ranjit missed his train.
Explanation: Indian Railways uses the 24-hour clock. '05:30' represents 5:30 am in the early morning. If the train were at 5:30 in the evening, the ticket would have printed '17:30'. Since Ranjit arrived at 5:00 pm (17:00), his train had already departed 11 hours and 30 minutes earlier.
Explanation: Indian Railways uses the 24-hour clock. '05:30' represents 5:30 am in the early morning. If the train were at 5:30 in the evening, the ticket would have printed '17:30'. Since Ranjit arrived at 5:00 pm (17:00), his train had already departed 11 hours and 30 minutes earlier.
Rubric: 1 Mark for missed train conclusion; 1 Mark for explaining 05:30 am vs 17:30 pm.