Lesson Planning of Conversion of Units of Lengths
Subject Mathematics
Grade 4^{th}
Students` Learning Outcomes
 Convert centimetres to millimetres and vice versa
Information for Teachers
 A millimetre is onethousandth of a meter shortly written as “mm”.
 It is roughly thickness of our finger nail or a paperclip and the smallest measurement unit on a scale.
 Centimeter is further divided into a smaller unit ‘millimetres’.
 1 centimeter = 10 millimetres.
 Multiply the centimeter by 10 to get millimetre, as; mm = cm x 10.
 Divide the number of millimetres by 10 to get centimetres. , as
 During this lesson the teacher should consult with textbook at each level where required.
Material / Resources
Measuring tape, scale, writing board, chalk/marker, duster, prints of fee and hand, flashcards, textbook
Introduction
 Ask the students today we will know to convert centimetres to millimetre and millimetres to centimetres.
 Ask the students in which units do you think the length and thickness of your nail can be measured?
 Quote examples from daily life as; a rain gauge (instrument which is used to measure the amount of rain) which measures rain in millimetres.
 Ask the students to bring out their scales and observe the centimeter and millimetre lines.
 Tell them between any two centimetres lines there are 10 small lines represent millimetres.
Development
Activity 1

Activity 2

Activity 3

Sum up / Conclusion
 1 cm can be further divided into smaller unit’s known as millimetres.
 A Millimetres is the smallest unit of measurement shortly written as; “mm”.
 1 cm = 10 mm
 Multiply the centimetres by 10 to get millimetres, as; mm = cm x 10.
 Divide the number of millimetres by 10 to get centimetres, as cm = mm ÷10
Assessment
 Distribute the following questions among the students and ask them to choose the best answer, as ;
 The paper clip is 3 ______ long.
(a) Centimetres (b) kilometres
 The scale shown on ruler is in ________.
(a) Meters (b) centimetres
 Lead of pencil is measured in _________.
(a) Centimetres (b) millimetres
 Ayesha`s geometry is ______ long.
(a) Millimetres (b) centimetres
Follow up
 Nadir measured a line of his art project. It is 200 mm long. How many centimetres is the line?
 Javed`s shoe box is 20 cm long and 10 cm wide. How many more millimetres is the length of the shoes box than the width?
 Seema has 42 cm long piece of 3 equal lengths. How long should each piece be in millimetres?
 My younger sister asked me to tie up her gas balloon with a long thread. I took a 50 cm long thread. What is the length of the thread in millimetres?