Learning Objectives (अधिगम उद्देश्य)
By the end of the lesson, students will be able to:
English:
- Understand the concept of length and measurement.
- Identify different units of length.
- Convert larger units into smaller units and vice versa.
- Measure objects using standard units.
- Add and subtract measurements of length.
- Solve real-life problems related to length.
हिंदी:
- लंबाई और मापन की अवधारणा समझ सकेंगे।
- लंबाई की विभिन्न इकाइयों को पहचान सकेंगे।
- बड़ी इकाइयों को छोटी इकाइयों में और छोटी इकाइयों को बड़ी इकाइयों में बदल सकेंगे।
- वस्तुओं की लंबाई माप सकेंगे।
- लंबाई के मापों का जोड़ और घटाव कर सकेंगे।
- दैनिक जीवन की लंबाई से संबंधित समस्याएँ हल कर सकेंगे।
Teaching Aids (शिक्षण सामग्री)
- Ruler (स्केल)
- Measuring tape (मापने वाली फीता)
- Meter scale (मीटर स्केल)
- Objects like books, pencils, desks
- Conversion chart
- Worksheets
Previous Knowledge (पूर्व ज्ञान)
Students know:
- Counting numbers
- Basic comparison (longer/shorter)
- Units like metre and centimetre
Day 1: Introduction to Length (लंबाई का परिचय)
Activity: Measuring Objects (वस्तुओं को मापना)
Teacher shows:
- Pencil
- Book
- Table
Ask students:
"Which object is longer?"
Students compare and answer.
Teacher explains:
To know the exact length of an object, we use measurement.
Study Material: Length (लंबाई)
Definition:
English:
Length is the measurement of distance from one end of an object to another end.
Hindi:
किसी वस्तु के एक छोर से दूसरे छोर तक की दूरी को लंबाई कहते हैं।
Units of Length (लंबाई की इकाइयाँ)
The standard units of length are:
Unit
Symbol
Use
Millimetre
mm
Very small objects
Centimetre
cm
Small objects
Metre
m
Large objects
Kilometre
km
Long distances
Examples:
- Length of pencil = 15 cm
- Height of a door = 2 m
- Distance between two cities = 200 km
Important Conversions (महत्वपूर्ण परिवर्तन)
10 millimetres (mm) = 1 centimetre (cm)
100 centimetres (cm) = 1 metre (m)
1000 metres (m) = 1 kilometre (km)
Classroom Practice:
Fill in the blanks:
- 100 cm = ____ m
- 1000 m = ____ km
- 10 mm = ____ cm
Day 2: Measuring Length (लंबाई मापना)
Using a Ruler (स्केल से मापना)
Steps:
- Place the zero mark at the beginning of the object.
- Look at the other end.
- Read the measurement.
Steps in Hindi:
- वस्तु के प्रारंभिक छोर को शून्य पर रखें।
- दूसरे छोर पर संख्या देखें।
- लंबाई लिखें।
Example:
A pencil starts from 0 cm and ends at 12 cm.
Length of pencil = 12 cm
Activity:
Measure:
- Pencil = ____ cm
- Notebook = ____ cm
- Eraser = ____ cm
Day 3: Conversion of Units (इकाइयों का परिवर्तन)
Conversion from Bigger Unit to Smaller Unit
Rule:
Multiply when changing bigger unit into smaller unit.
बड़ी इकाई को छोटी इकाई में बदलने के लिए गुणा करते हैं।
Examples:
1 m = 100 cm
5 m = 5 × 100
= 500 cm
2 km = 2 × 1000
= 2000 m
Conversion from Smaller Unit to Bigger Unit
Divide when changing smaller unit into bigger unit.
छोटी इकाई को बड़ी इकाई में बदलने के लिए भाग करते हैं।
Example:
300 cm = 300 ÷ 100
= 3 m
Practice:
Convert:
- 6 m = ____ cm
- 800 cm = ____ m
- 4 km = ____ m
- 5000 m = ____ km
Day 4: Addition and Subtraction of Length (लंबाई का जोड़ और घटाव)
Addition of Length
Example:
Add:
5 m 25 cm + 3 m 40 cm
5 m 25 cm + 3 m 40 cm ------------- 8 m 65 cm
Subtraction of Length
Example:
8 m 50 cm - 3 m 20 cm
8 m 50 cm - 3 m 20 cm ------------- 5 m 30 cm
Word Problems (शब्द समस्याएँ)
Question 1:
A rope is 15 m long. Another rope is 10 m long. Find the total length.
Solution:
15 m + 10 m = 25 m
Answer: 25 metres
Question 2:
A ribbon is 20 m long. 8 m is used. How much ribbon is left?
Solution:
20 m - 8 m = 12 m
Answer: 12 metres
Day 5: Application and Revision (प्रयोग और पुनरावृत्ति)
Uses of Length Measurement (लंबाई मापन के उपयोग)
Length is used in:
- Measuring height (ऊँचाई मापने में)
- Measuring cloth (कपड़ा मापने में)
- Measuring distance (दूरी मापने में)
- Construction work (निर्माण कार्य में)
Worksheet (अभ्यास पत्र)
A. Fill in the blanks:
- The standard unit of length is ______.
- 100 cm = ______ m.
- 1000 m = ______ km.
- A ruler is used to measure ______.
- 1 km = ______ m.
B. Choose the correct unit:
- Distance between two cities:
(a) cm (b) km (c) mm - Length of a pencil:
(a) cm (b) km (c) m - Height of a building:
(a) m (b) cm (c) mm
C. Convert:
- 7 m = ______ cm
- 900 cm = ______ m
- 5 km = ______ m
- 3000 m = ______ km
D. Add:
- 12 m 30 cm + 5 m 20 cm
- 8 m 45 cm + 6 m 25 cm
E. Subtract:
- 15 m 50 cm - 5 m 20 cm
- 20 m 75 cm - 8 m 25 cm
Assessment Questions (मूल्यांकन)
- What is length?
- Name the units of length.
- Convert 4 m into cm.
- Convert 3000 m into km.
- Add 6 m 25 cm and 3 m 50 cm.
Homework (गृहकार्य)
- Measure the length of five objects at home and write their measurements.
Object
Length
Pencil
Book
Table
Door
Bed
- Convert:
a) 9 m = ____ cm
b) 700 cm = ____ m
c) 6 km = ____ m
- Solve:
a) 25 m + 15 m
b) 30 m - 12 m