Lesson 7.2: Estimating, Measuring, and Comparing Lengths
Estimate lengths before measuring, solve addition/subtraction word problems involving length, and compare distances.
⏱️ Reading Time: 15 mins
• ❓ 50 Interactive Practice Questions
🌟
Real-Life Story: Measurement of Length
Students in a carpentry workshop build birdhouses. Before cutting timber, they estimate lengths with their hands, mark exact lines with a set square, and verify that 2 boards of 45 cm and 35 cm combine to 80 cm.
💡 Core Mathematical Concepts: Estimating & Comparing Lengths
Focus areas: Estimation, bench-marking, difference in length, multi-step word problems.
| Concept / Term | Mathematical Definition | Everyday Example |
|---|---|---|
| Estimation Benchmark | Using a known bodily or physical object to approximate length before measuring | A fingertip width is about 1 cm; an outstretched arm span is about 1 m |
| Length Addition & Subtraction | Combining lengths of the same unit directly; convert mixed units first | 1 m 20 cm + 2 m 30 cm = 3 m 50 cm |
| Comparing Lengths | Finding how much longer or shorter one object is than another by subtraction | A 180 cm rope is 30 cm longer than a 150 cm rope |
| Perimeter Introduction | The total distance around the outer boundary of a 2D shape | Adding all side lengths together |
🔍 Practical Classroom & Everyday Examples
Example 1: Unit Uniformity
Never add centimetres directly to metres without converting first (e.g., 2 m + 30 cm = 230 cm, NOT 32 m!).
Example 2: Rounding Lengths
Measure to the nearest centimetre when exact millimeter precision is not required.
⚠️ Watch Out! Common Mistakes to Avoid
Common Error: Adding different units directly
Correction: Adding 2 m + 50 cm and writing 52 m is a severe error (it is 2.5 m or 250 cm).
Common Error: Ignoring the zero offset on broken rulers
Correction: If measuring from 2 cm to 8 cm, the length is 8 - 2 = 6 cm, not 8 cm.
🎯 Quick Self-Check Challenge
A roll of ribbon is 5 metres long. Sarah cuts three 80 cm strips for gift wrapping. How much ribbon remains on the roll?
Answer & Explanation:
3 strips × 80 cm = 240 cm. Total ribbon = 5 m = 500 cm. Remaining ribbon = 500 cm - 240 cm = 260 cm (or 2 m 60 cm).
🎯 Key Learning Takeaways
Master Measurement of Length fundamentals.
📄 Printable Worksheets (5 Available)
Download ready-to-print PDFs for offline student practice with separate parent/teacher answer keys.
G3-M-CH07-WS05
A4 • 15 Qs
Measurement of Length — Worksheet 5
Metric Units, Ruler Precision & Conversions (Community Highway Expansion)
G3-M-CH07-WS04
A4 • 15 Qs
Measurement of Length — Worksheet 4
Metric Units, Ruler Precision & Conversions (Textile Fabric Weaving)
G3-M-CH07-WS03
A4 • 15 Qs
Measurement of Length — Worksheet 3
Metric Units, Ruler Precision & Conversions (Botanical Garden Walkway)
G3-M-CH07-WS02
A4 • 15 Qs
Measurement of Length — Worksheet 2
Metric Units, Ruler Precision & Conversions (Carpentry Wood Workshop)
G3-M-CH07-WS01
A4 • 15 Qs
Measurement of Length — Worksheet 1
Metric Units, Ruler Precision & Conversions (School Sports Track)
✍️ Lesson Practice Questions (50 Questions)
Solve these real-world challenges online, test your understanding, and reveal instant step-by-step explanations.
1
Short Answer
Hard
2 Marks
A wooden plank is 6 metres long. A carpenter cuts it into 5 equal pieces. What is the length of each piece in centimetres?
A
120 cm
B
100 cm
C
150 cm
D
125 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
120 cm
Step-by-Step Explanation:
6 m = 600 cm. 600 cm ÷ 5 = 120 cm per piece.
2
Short Answer
Hard
2 Marks
A school bus travels 3 km 400 m in the morning and 2 km 850 m in the afternoon. What is the total distance traveled by the bus in kilometres and metres?
A
6 km 250 m
B
5 km 250 m
C
6 km 150 m
D
5 km 850 m
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
6 km 250 m
Step-by-Step Explanation:
3 km + 2 km = 5 km. 400 m + 850 m = 1,250 m = 1 km 250 m. Total = 6 km 250 m.
3
Short Answer
Hard
2 Marks
If an ant walks 1,000 millimetres in a straight line, how many metres has the ant traveled?
A
1 metre
B
10 metres
C
0.1 metre
D
100 metres
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
10 metres
Step-by-Step Explanation:
1 cm = 10 mm; 1 m = 100 cm = 1,000 mm. So 1,000 mm = 1 metre.
4
Short Answer
Hard
2 Marks
Why would measuring a classroom with a 15 cm school ruler be less accurate and practical than using a 5-metre tape measure?
A
Moving a 15 cm ruler repeatedly introduces cumulative alignment errors and takes much longer, whereas a tape measure spans the room in one continuous measurement
B
A 15 cm ruler measures in inches
C
Tape measures are only used outside
D
School rulers shrink in classroom light
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
Moving a 15 cm ruler repeatedly introduces cumulative alignment errors and takes much longer, whereas a tape measure spans the room in one continuous measurement
Step-by-Step Explanation:
Repeated repositioning of small instruments accumulates human positioning errors.
5
Short Answer
Medium
1 Mark
Priya calculates: '2 m + 35 cm = 37 m'. What conceptual mistake did Priya make?
A
She added metres and centimetres directly without converting units; the correct answer is 2 m 35 cm (235 cm)
B
She should have subtracted
C
2 m is equal to 20 cm
D
There is no mistake
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
She added metres and centimetres directly without converting units; the correct answer is 2 m 35 cm (235 cm)
Step-by-Step Explanation:
Different metric units cannot be added directly without converting to a common unit.
6
Short Answer
Medium
1 Mark
A student measures a pencil with a broken ruler starting at the 3 cm mark and ending at 11 cm. He records the length as '11 cm'. What is the true length?
A
8 cm (11 - 3 = 8 cm)
B
11 cm
C
14 cm
D
9 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
8 cm (11 - 3 = 8 cm)
Step-by-Step Explanation:
When not starting from zero, subtract the start mark from the end mark: 11 - 3 = 8 cm.
7
Fill in the Blanks
Medium
1 Mark
Find the missing length: 3 m 40 cm + [ ? ] cm = 4 m
A
60 cm
B
50 cm
C
70 cm
D
40 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
60 cm
Step-by-Step Explanation:
4 m = 400 cm. 400 cm - 340 cm = 60 cm.
8
Fill in the Blanks
Medium
1 Mark
Find the missing value: 5 km = [ ? ] m
A
5,000 m
B
500 m
C
50,000 m
D
50 m
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
5,000 m
Step-by-Step Explanation:
1 km = 1,000 m, so 5 km = 5,000 m.
9
Short Answer
Medium
1 Mark
Liam is 135 cm tall and his older sister is 1 m 58 cm tall. How many centimetres taller is his sister?
A
23 cm
B
25 cm
C
18 cm
D
33 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
23 cm
Step-by-Step Explanation:
Sister = 1 m 58 cm = 158 cm. Difference = 158 - 135 = 23 cm.
10
Short Answer
Medium
1 Mark
A tailor has a 4-metre piece of fabric. She cuts 120 cm for a shirt and 150 cm for trousers. How many centimetres of fabric remain?
A
130 cm
B
150 cm
C
120 cm
D
170 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
130 cm
Step-by-Step Explanation:
Total = 4 m = 400 cm. Used = 120 + 150 = 270 cm. Remaining = 400 - 270 = 130 cm.
11
Short Answer
Medium
1 Mark
At the Community Highway Expansion, an athlete runs 4 laps of a 250-metre course. What total distance does the athlete run?
A
1000 metres
B
950 metres
C
1100 metres
D
500 metres
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
1000 metres
Step-by-Step Explanation:
4 × 250 m = 1000 metres.
12
Multiple Choice
Easy
1 Mark
Which metric unit is most suitable for measuring the distance between two cities?
A
Kilometres (km)
B
Centimetres (cm)
C
Millimetres (mm)
D
Metres (m)
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
Kilometres (km)
Step-by-Step Explanation:
Long geographic travel distances are measured in kilometres.
13
Multiple Choice
Easy
1 Mark
Convert 2 m 65 cm into total centimetres:
A
265 cm
B
2,065 cm
C
205 cm
D
2,650 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
265 cm
Step-by-Step Explanation:
2 m = 200 cm. 200 + 65 = 265 cm.
14
Multiple Choice
Easy
1 Mark
How many metres are in 3 kilometres?
A
3,000 m
B
300 m
C
30 m
D
30,000 m
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
3,000 m
Step-by-Step Explanation:
1 kilometre = 1,000 metres. 3 × 1,000 = 3,000 m.
15
Multiple Choice
Easy
1 Mark
How many centimetres are there in 4 metres?
A
400 cm
B
40 cm
C
4,000 cm
D
140 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
400 cm
Step-by-Step Explanation:
1 metre = 100 cm. 4 × 100 = 400 cm.
16
Short Answer
Hard
2 Marks
A wooden plank is 6 metres long. A carpenter cuts it into 5 equal pieces. What is the length of each piece in centimetres?
A
120 cm
B
100 cm
C
150 cm
D
125 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
120 cm
Step-by-Step Explanation:
6 m = 600 cm. 600 cm ÷ 5 = 120 cm per piece.
17
Short Answer
Hard
2 Marks
A school bus travels 3 km 400 m in the morning and 2 km 850 m in the afternoon. What is the total distance traveled by the bus in kilometres and metres?
A
6 km 250 m
B
5 km 250 m
C
6 km 150 m
D
5 km 850 m
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
6 km 250 m
Step-by-Step Explanation:
3 km + 2 km = 5 km. 400 m + 850 m = 1,250 m = 1 km 250 m. Total = 6 km 250 m.
18
Short Answer
Hard
2 Marks
If an ant walks 1,000 millimetres in a straight line, how many metres has the ant traveled?
A
1 metre
B
10 metres
C
0.1 metre
D
100 metres
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
10 metres
Step-by-Step Explanation:
1 cm = 10 mm; 1 m = 100 cm = 1,000 mm. So 1,000 mm = 1 metre.
19
Short Answer
Hard
2 Marks
Why would measuring a classroom with a 15 cm school ruler be less accurate and practical than using a 5-metre tape measure?
A
Moving a 15 cm ruler repeatedly introduces cumulative alignment errors and takes much longer, whereas a tape measure spans the room in one continuous measurement
B
A 15 cm ruler measures in inches
C
Tape measures are only used outside
D
School rulers shrink in classroom light
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
Moving a 15 cm ruler repeatedly introduces cumulative alignment errors and takes much longer, whereas a tape measure spans the room in one continuous measurement
Step-by-Step Explanation:
Repeated repositioning of small instruments accumulates human positioning errors.
20
Short Answer
Medium
1 Mark
Priya calculates: '2 m + 35 cm = 37 m'. What conceptual mistake did Priya make?
A
She added metres and centimetres directly without converting units; the correct answer is 2 m 35 cm (235 cm)
B
She should have subtracted
C
2 m is equal to 20 cm
D
There is no mistake
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
She added metres and centimetres directly without converting units; the correct answer is 2 m 35 cm (235 cm)
Step-by-Step Explanation:
Different metric units cannot be added directly without converting to a common unit.
21
Short Answer
Medium
1 Mark
A student measures a pencil with a broken ruler starting at the 3 cm mark and ending at 11 cm. He records the length as '11 cm'. What is the true length?
A
8 cm (11 - 3 = 8 cm)
B
11 cm
C
14 cm
D
9 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
8 cm (11 - 3 = 8 cm)
Step-by-Step Explanation:
When not starting from zero, subtract the start mark from the end mark: 11 - 3 = 8 cm.
22
Fill in the Blanks
Medium
1 Mark
Find the missing length: 3 m 40 cm + [ ? ] cm = 4 m
A
60 cm
B
50 cm
C
70 cm
D
40 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
60 cm
Step-by-Step Explanation:
4 m = 400 cm. 400 cm - 340 cm = 60 cm.
23
Fill in the Blanks
Medium
1 Mark
Find the missing value: 5 km = [ ? ] m
A
5,000 m
B
500 m
C
50,000 m
D
50 m
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
5,000 m
Step-by-Step Explanation:
1 km = 1,000 m, so 5 km = 5,000 m.
24
Short Answer
Medium
1 Mark
Liam is 135 cm tall and his older sister is 1 m 58 cm tall. How many centimetres taller is his sister?
A
23 cm
B
25 cm
C
18 cm
D
33 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
23 cm
Step-by-Step Explanation:
Sister = 1 m 58 cm = 158 cm. Difference = 158 - 135 = 23 cm.
25
Short Answer
Medium
1 Mark
A tailor has a 4-metre piece of fabric. She cuts 120 cm for a shirt and 150 cm for trousers. How many centimetres of fabric remain?
A
130 cm
B
150 cm
C
120 cm
D
170 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
130 cm
Step-by-Step Explanation:
Total = 4 m = 400 cm. Used = 120 + 150 = 270 cm. Remaining = 400 - 270 = 130 cm.
26
Short Answer
Medium
1 Mark
At the Textile Fabric Weaving, an athlete runs 5 laps of a 80-metre course. What total distance does the athlete run?
A
400 metres
B
350 metres
C
500 metres
D
200 metres
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
400 metres
Step-by-Step Explanation:
5 × 80 m = 400 metres.
27
Multiple Choice
Easy
1 Mark
Which metric unit is most suitable for measuring the distance between two cities?
A
Kilometres (km)
B
Centimetres (cm)
C
Millimetres (mm)
D
Metres (m)
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
Kilometres (km)
Step-by-Step Explanation:
Long geographic travel distances are measured in kilometres.
28
Multiple Choice
Easy
1 Mark
Convert 2 m 65 cm into total centimetres:
A
265 cm
B
2,065 cm
C
205 cm
D
2,650 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
265 cm
Step-by-Step Explanation:
2 m = 200 cm. 200 + 65 = 265 cm.
29
Multiple Choice
Easy
1 Mark
How many metres are in 3 kilometres?
A
3,000 m
B
300 m
C
30 m
D
30,000 m
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
3,000 m
Step-by-Step Explanation:
1 kilometre = 1,000 metres. 3 × 1,000 = 3,000 m.
30
Multiple Choice
Easy
1 Mark
How many centimetres are there in 4 metres?
A
400 cm
B
40 cm
C
4,000 cm
D
140 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
400 cm
Step-by-Step Explanation:
1 metre = 100 cm. 4 × 100 = 400 cm.
31
Short Answer
Hard
2 Marks
A wooden plank is 6 metres long. A carpenter cuts it into 5 equal pieces. What is the length of each piece in centimetres?
A
120 cm
B
100 cm
C
150 cm
D
125 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
120 cm
Step-by-Step Explanation:
6 m = 600 cm. 600 cm ÷ 5 = 120 cm per piece.
32
Short Answer
Hard
2 Marks
A school bus travels 3 km 400 m in the morning and 2 km 850 m in the afternoon. What is the total distance traveled by the bus in kilometres and metres?
A
6 km 250 m
B
5 km 250 m
C
6 km 150 m
D
5 km 850 m
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
6 km 250 m
Step-by-Step Explanation:
3 km + 2 km = 5 km. 400 m + 850 m = 1,250 m = 1 km 250 m. Total = 6 km 250 m.
33
Short Answer
Hard
2 Marks
If an ant walks 1,000 millimetres in a straight line, how many metres has the ant traveled?
A
1 metre
B
10 metres
C
0.1 metre
D
100 metres
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
10 metres
Step-by-Step Explanation:
1 cm = 10 mm; 1 m = 100 cm = 1,000 mm. So 1,000 mm = 1 metre.
34
Short Answer
Hard
2 Marks
Why would measuring a classroom with a 15 cm school ruler be less accurate and practical than using a 5-metre tape measure?
A
Moving a 15 cm ruler repeatedly introduces cumulative alignment errors and takes much longer, whereas a tape measure spans the room in one continuous measurement
B
A 15 cm ruler measures in inches
C
Tape measures are only used outside
D
School rulers shrink in classroom light
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
Moving a 15 cm ruler repeatedly introduces cumulative alignment errors and takes much longer, whereas a tape measure spans the room in one continuous measurement
Step-by-Step Explanation:
Repeated repositioning of small instruments accumulates human positioning errors.
35
Short Answer
Medium
1 Mark
Priya calculates: '2 m + 35 cm = 37 m'. What conceptual mistake did Priya make?
A
She added metres and centimetres directly without converting units; the correct answer is 2 m 35 cm (235 cm)
B
She should have subtracted
C
2 m is equal to 20 cm
D
There is no mistake
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
She added metres and centimetres directly without converting units; the correct answer is 2 m 35 cm (235 cm)
Step-by-Step Explanation:
Different metric units cannot be added directly without converting to a common unit.
36
Short Answer
Medium
1 Mark
A student measures a pencil with a broken ruler starting at the 3 cm mark and ending at 11 cm. He records the length as '11 cm'. What is the true length?
A
8 cm (11 - 3 = 8 cm)
B
11 cm
C
14 cm
D
9 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
8 cm (11 - 3 = 8 cm)
Step-by-Step Explanation:
When not starting from zero, subtract the start mark from the end mark: 11 - 3 = 8 cm.
37
Fill in the Blanks
Medium
1 Mark
Find the missing length: 3 m 40 cm + [ ? ] cm = 4 m
A
60 cm
B
50 cm
C
70 cm
D
40 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
60 cm
Step-by-Step Explanation:
4 m = 400 cm. 400 cm - 340 cm = 60 cm.
38
Fill in the Blanks
Medium
1 Mark
Find the missing value: 5 km = [ ? ] m
A
5,000 m
B
500 m
C
50,000 m
D
50 m
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
5,000 m
Step-by-Step Explanation:
1 km = 1,000 m, so 5 km = 5,000 m.
39
Short Answer
Medium
1 Mark
Liam is 135 cm tall and his older sister is 1 m 58 cm tall. How many centimetres taller is his sister?
A
23 cm
B
25 cm
C
18 cm
D
33 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
23 cm
Step-by-Step Explanation:
Sister = 1 m 58 cm = 158 cm. Difference = 158 - 135 = 23 cm.
40
Short Answer
Medium
1 Mark
A tailor has a 4-metre piece of fabric. She cuts 120 cm for a shirt and 150 cm for trousers. How many centimetres of fabric remain?
A
130 cm
B
150 cm
C
120 cm
D
170 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
130 cm
Step-by-Step Explanation:
Total = 4 m = 400 cm. Used = 120 + 150 = 270 cm. Remaining = 400 - 270 = 130 cm.
41
Short Answer
Medium
1 Mark
At the Botanical Garden Walkway, an athlete runs 3 laps of a 200-metre course. What total distance does the athlete run?
A
600 metres
B
550 metres
C
700 metres
D
300 metres
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
600 metres
Step-by-Step Explanation:
3 × 200 m = 600 metres.
42
Multiple Choice
Easy
1 Mark
Which metric unit is most suitable for measuring the distance between two cities?
A
Kilometres (km)
B
Centimetres (cm)
C
Millimetres (mm)
D
Metres (m)
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
Kilometres (km)
Step-by-Step Explanation:
Long geographic travel distances are measured in kilometres.
43
Multiple Choice
Easy
1 Mark
Convert 2 m 65 cm into total centimetres:
A
265 cm
B
2,065 cm
C
205 cm
D
2,650 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
265 cm
Step-by-Step Explanation:
2 m = 200 cm. 200 + 65 = 265 cm.
44
Multiple Choice
Easy
1 Mark
How many metres are in 3 kilometres?
A
3,000 m
B
300 m
C
30 m
D
30,000 m
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
3,000 m
Step-by-Step Explanation:
1 kilometre = 1,000 metres. 3 × 1,000 = 3,000 m.
45
Multiple Choice
Easy
1 Mark
How many centimetres are there in 4 metres?
A
400 cm
B
40 cm
C
4,000 cm
D
140 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
400 cm
Step-by-Step Explanation:
1 metre = 100 cm. 4 × 100 = 400 cm.
46
Short Answer
Hard
2 Marks
A wooden plank is 6 metres long. A carpenter cuts it into 5 equal pieces. What is the length of each piece in centimetres?
A
120 cm
B
100 cm
C
150 cm
D
125 cm
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
120 cm
Step-by-Step Explanation:
6 m = 600 cm. 600 cm ÷ 5 = 120 cm per piece.
47
Short Answer
Hard
2 Marks
A school bus travels 3 km 400 m in the morning and 2 km 850 m in the afternoon. What is the total distance traveled by the bus in kilometres and metres?
A
6 km 250 m
B
5 km 250 m
C
6 km 150 m
D
5 km 850 m
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
6 km 250 m
Step-by-Step Explanation:
3 km + 2 km = 5 km. 400 m + 850 m = 1,250 m = 1 km 250 m. Total = 6 km 250 m.
48
Short Answer
Hard
2 Marks
If an ant walks 1,000 millimetres in a straight line, how many metres has the ant traveled?
A
1 metre
B
10 metres
C
0.1 metre
D
100 metres
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
10 metres
Step-by-Step Explanation:
1 cm = 10 mm; 1 m = 100 cm = 1,000 mm. So 1,000 mm = 1 metre.
49
Short Answer
Hard
2 Marks
Why would measuring a classroom with a 15 cm school ruler be less accurate and practical than using a 5-metre tape measure?
A
Moving a 15 cm ruler repeatedly introduces cumulative alignment errors and takes much longer, whereas a tape measure spans the room in one continuous measurement
B
A 15 cm ruler measures in inches
C
Tape measures are only used outside
D
School rulers shrink in classroom light
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
Moving a 15 cm ruler repeatedly introduces cumulative alignment errors and takes much longer, whereas a tape measure spans the room in one continuous measurement
Step-by-Step Explanation:
Repeated repositioning of small instruments accumulates human positioning errors.
50
Short Answer
Medium
1 Mark
Priya calculates: '2 m + 35 cm = 37 m'. What conceptual mistake did Priya make?
A
She added metres and centimetres directly without converting units; the correct answer is 2 m 35 cm (235 cm)
B
She should have subtracted
C
2 m is equal to 20 cm
D
There is no mistake
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
She added metres and centimetres directly without converting units; the correct answer is 2 m 35 cm (235 cm)
Step-by-Step Explanation:
Different metric units cannot be added directly without converting to a common unit.