Length Word Problems (Grade 3)
Length word problems in Class 3 involve measuring, comparing, adding, and subtracting lengths using centimetres (cm) and metres (m).
These problems use real-life situations like measuring ribbon, comparing heights, finding the length of a room, or calculating how far someone walked. You need to read the problem carefully, pick the right operation, and sometimes convert between cm and m.
Remember: 1 metre = 100 centimetres. This conversion is key to solving many length word problems.
What is Length Word Problems - Class 3 Maths (Measurement (Grade 3))?
Length is the measurement of how long something is from one end to the other.
1 m = 100 cm
Standard units used in Class 3:
- Centimetre (cm) — for short lengths (pencil, book, hand span)
- Metre (m) — for longer lengths (room, corridor, playground)
Operations used in length word problems:
- Addition — finding total length
- Subtraction — finding difference in length or remaining length
- Conversion — changing m to cm or cm to m
Solved Examples
Example 1: Example 1: Adding Lengths
Question: Ria's ribbon is 45 cm long. Priya's ribbon is 38 cm long. What is the total length of both ribbons?
Think:
- Total = 45 + 38 = 83 cm
Answer: The total length is 83 cm.
Example 2: Example 2: Subtracting Lengths
Question: A rope is 2 m 50 cm long. Aman cuts off 80 cm. How long is the remaining rope?
Think:
- Convert: 2 m 50 cm = 250 cm
- Subtract: 250 − 80 = 170 cm
- Convert back: 170 cm = 1 m 70 cm
Answer: The remaining rope is 1 m 70 cm.
Example 3: Example 3: Comparing Heights
Question: Dev is 1 m 25 cm tall. Arjun is 1 m 18 cm tall. How much taller is Dev?
Think:
- Dev = 125 cm, Arjun = 118 cm
- Difference = 125 − 118 = 7 cm
Answer: Dev is 7 cm taller than Arjun.
Example 4: Example 4: Converting and Adding
Question: Neha walks 3 m in the morning and 250 cm in the evening. What is the total distance she walks?
Think:
- Convert: 3 m = 300 cm
- Total = 300 + 250 = 550 cm
- Convert: 550 cm = 5 m 50 cm
Answer: Neha walks 5 m 50 cm in total.
Example 5: Example 5: Finding Remaining Length
Question: A cloth is 5 m long. A tailor uses 2 m 30 cm. How much cloth is left?
Think:
- 5 m = 500 cm
- 2 m 30 cm = 230 cm
- Remaining = 500 − 230 = 270 cm = 2 m 70 cm
Answer: 2 m 70 cm of cloth is left.
Example 6: Example 6: Multiple Pieces
Question: Kavi cuts a wire into 4 equal pieces. The wire is 60 cm long. How long is each piece?
Think:
- Total length = 60 cm
- Number of pieces = 4
- Each piece = 60 ÷ 4 = 15 cm
Answer: Each piece is 15 cm long.
Example 7: Example 7: Perimeter Context
Question: Aditi walks around a rectangular garden that is 8 m long and 5 m wide. How far does she walk in one round?
Think:
- Perimeter = 2 × (length + width)
- Perimeter = 2 × (8 + 5) = 2 × 13 = 26 m
Answer: Aditi walks 26 m in one round.
Example 8: Example 8: Two-Step Problem
Question: Rahul has a stick that is 1 m long. He breaks off 25 cm, then breaks off another 40 cm. How long is the remaining stick?
Think:
- 1 m = 100 cm
- After first break: 100 − 25 = 75 cm
- After second break: 75 − 40 = 35 cm
Answer: The remaining stick is 35 cm long.
Example 9: Example 9: Comparing Lengths
Question: Meera's pencil is 15 cm long. Priya's pencil is 9 cm long. How much longer is Meera's pencil?
Think:
- Difference = 15 − 9 = 6 cm
Answer: Meera's pencil is 6 cm longer.
Example 10: Example 10: Total of Three Lengths
Question: Three strips of paper are 22 cm, 18 cm, and 35 cm long. What is their total length?
Think:
- 22 + 18 + 35 = 75 cm
Answer: The total length is 75 cm.
Real-World Applications
Where Do We Solve Length Word Problems?
- Tailoring: Measuring and cutting cloth for dresses and curtains.
- Carpentry: Measuring wood pieces for furniture.
- Sports: Measuring the length of a cricket pitch (22 yards) or a running track.
- Gardening: Measuring the length of a garden bed or fence.
- Height comparison: Comparing heights of children or objects.
Key Points to Remember
- 1 m = 100 cm — the most important conversion.
- Convert all measurements to the same unit before adding or subtracting.
- Addition gives total length; subtraction gives difference or remaining length.
- Read the problem carefully to decide which operation to use.
- Convert back to m and cm if the answer is more than 100 cm.
- Use cm for small objects and m for large objects.
Practice Problems
- A rope is 3 m 40 cm long. Another rope is 2 m 60 cm long. What is the total length?
- Dev's pencil is 18 cm. He sharpens it and it becomes 15 cm. How much shorter is it now?
- A table is 1 m 50 cm long. A bookshelf is 2 m 10 cm long. How much longer is the bookshelf?
- Ria has 5 m of ribbon. She cuts pieces of 1 m 20 cm and 2 m 30 cm. How much ribbon is left?
- Four sticks are each 25 cm long. What is their total length in metres and centimetres?
- Aman walks 400 m to school and 250 m to the park after school. How far does he walk in total?
- A wire is 200 cm long. It is cut into 5 equal pieces. How long is each piece?
Frequently Asked Questions
Q1. How many centimetres are in 1 metre?
1 metre = 100 centimetres. To convert metres to centimetres, multiply by 100.
Q2. How do I convert cm to m?
Divide by 100. For example, 350 cm = 3 m 50 cm (350 ÷ 100 = 3 remainder 50).
Q3. When do I add lengths in a word problem?
Add when the problem asks for the total, combined, or together length. Key words: total, altogether, combined, in all.
Q4. When do I subtract lengths?
Subtract when the problem asks how much is left, the difference, or how much longer/shorter. Key words: left, remaining, difference, more than, less than.
Q5. Why do I need to convert before adding?
You cannot add metres and centimetres directly. Convert everything to the same unit first, then add or subtract.
Q6. What is the best unit for measuring a classroom?
Use metres (m) for a classroom. Classrooms are typically 8–10 metres long. Centimetres would give very large numbers.
Q7. How do I write 2 m 50 cm in centimetres only?
2 m = 200 cm. So 2 m 50 cm = 200 + 50 = 250 cm.
Q8. Can I use multiplication in length problems?
Yes. If you have 5 ribbons each 30 cm long, the total is 5 × 30 = 150 cm = 1 m 50 cm.
Q9. What tools are used to measure length?
A ruler (for cm), a metre stick or measuring tape (for m), and a trundle wheel (for longer distances) are common tools.
