UNITS OF LENGTH

LESSON PLANNING OF USE APPROPRIATE UNITS OF LENGTH TO MEASURE THE OBJECTS

Subject Mathematics

Students` Learning Outcomes

• Use appropriate units of length to measure (with straightedge / ruler) the objects.
• Solve real life problems involving measurements.

Information for Teachers

• In the past, people used different organs of their body (foot, arm, hand, finger etc.) to measure length of any object.

• With the passage of time changes occurred and different instruments (inch tape, meter rod, guzz etc.) and units (inch, foot, guzz etc.) were introduced at different places for length measurement.
• At time passed, man-made new standards of measurement i.e. made standard units and instruments, in order to establish standard system for the measurement everywhere.

• While teaching the lesson, the teacher should also consult textbook at all steps where and when applicable.

Material / Resources

Writing board, chalk / marker, duster, meter rod, ruler with centimeter marks, measuring tape, rope pieces, and straws, textbook

Introduction

• Ask following questions from students;
• Show them a meter rod and ask what this is?

• For what purpose it is used?

• What type of objects we measure by using meter rod?
• What is the small unit of length?

• Which symbol is used to represent meter?( m)

Activity

• Hold two threads in your both hands and show to students.

• Ask the students, if the length of one rope is 2 m and other rope is also 2 m then what will be total length of both ropes?
• If they can`t reply then keep both ropes in a line and measure total length by meter rod in front of them.

• Similarly ask them, if the length of this rope is 2 m and I cut 1 m length then how much length left?
• Demonstrate in front of them.

Development

Activity 1

• Divide the class in 6 groups and provide them meter rods and centimeter rulers.
• Ask the groups to measure the following objects.

Group 1: One side of table.

Group 2: Door

Group 3: Heights of each other.

Group 4: Arms of each other.

Group 5: Chalks of different sizes.

Group 6: Leaves of different sizes

• Ask all groups to write measurement / length on their notebooks using appropriate.

Activity 2

• Call one student in front of class and give him a straw.
• Ask him to measure the length of the straw and write on board e.g. 14 cm.

• Then give him another straw and ask him to measure and write length on board e.g. 14 cm.
• Then ask from students: can we measure these two straws together? How?
• Ask the students to measure the total length by placing them in a line.
• Write the answer in any corner of board. (28 cm)
• Tell the students that we can find total length by adding these lengths.
• Add both lengths by placing these lengths in vertical form with units and tell them the answer is same as they find by measurement
• Repeat above steps for subtraction. For this, cut some part of straw and ask students to see how much is left?

Activity 3

• Call two students.
• Give one rope to each and ask them to measure.
• Now write the word problem by using names and measurements of both students.
• For example;

• Solve this question with the help of students and tell them we place value below value and unit below unit and write a addition symbol with them.
• Repeat this activity also for subtraction process.
• For practice, write some questions on paper strip and give students to solve in groups.

Sum up / Conclusion

• Tell the students that ‘total’ means addition. Tell the students that ‘left’ means subtraction.
• Repeat the methods of solving word problems of addition and subtraction.

Assessment

• Give following questions to students.