Maharashtra Board Class 4 Maths Part Two Chapter 11 Measurement PDF Download

11. Measurement

Length

A girl is measuring something with a ruler. She says: "The length I have measured is more than 5 centimetres but less than 6 centimetres. How do I measure this length?"

Another girl shows her a ruler and says: "Here, take this ruler. There are smaller markings between two adjacent centimetre markings. You will find them useful."

The first girl measures again and says: "The length I have measured is 5 centimetres and 3 small parts."

One centimetre is divided into 10 equal parts. Each part is called a millimetre.

It means that the length I have measured is 5 centimetres and 3 millimetres.

1 centimetre = 10 millimetres.

Centimetre is written in short as 'cm'.

Millimetre is written in short as 'mm'.

The length of this line is 5 cm. That is, 5 × 10 = 50 mm.

When a ruler is held along a line with its first marking at one end of the line, then the number at the other end of the line shows the length of the line.

How many mm is 7 cm?

7 × 10 = 70. So, 7cm = 70 mm.

Teacher's Note

You use a ruler to measure your pencil or book at home. A centimetre is like one small box in your notebook - very small!

Exam Trick

Remember: 1 cm = 10 mm. So multiply centimetres by 10 to get millimetres. It is like converting rupees to paise - multiply by 100!

Points to Remember

Centimetre and millimetre are units for measuring short lengths.
1 centimetre = 10 millimetres.
Use 'cm' for centimetre and 'mm' for millimetre.
A ruler helps us measure length correctly.
Always place the ruler's zero mark at the start of the line.

Exercise

Measure the length of the lines shown below and convert into millimetres.

(1) _________________ cm × 10 = _______ mm

(2) _________________ cm × _______ = _______ mm

Measuring The Length Of A Line In Centimetres And Millimetres

The length of the line shown above is 7 centimetres and 5 millimetres.

Measure the length of each line below and write how many centimetres and millimetres.

(1) _____________ _______ cm _______ mm

(2) _____________ _______ cm _______ mm

Measure and write.

A boy named Vivek asks: "I have an old ruler which shows centimetres and millimetres. But, the first end is broken. Will I be able to use it to measure centimetres?"

A teacher named Tai answers: "Oh, yes! Your ruler has a 3 centimetre mark and every centimetre mark after that. So you can start at 3 and measure the length from there. Can you do that?"

Vivek says: "Yes. The length of this pencil is from 3 centimetres to 9 centimetres."

A girl named Meera says: "If it is from 3 cm to 9 cm, you must subtract 3 from 9. The pencil is 6 centimetres long."

Teacher's Note

Even if your scale is broken, you can still measure. Start from any number that is clear and subtract at the end. Like measuring from the 2 mark instead of 0!

Exam Trick

If the ruler's starting point is broken, always subtract the starting number from the ending number. For example: 9 - 3 = 6 cm.

Points to Remember

A broken ruler can still be used for measurement.
Always subtract the starting point from the ending point.
The ruler must have clear markings to use it correctly.
Measure carefully and double-check your answer.
Write your answer with both cm and mm if needed.

Try This

Guess the length of the pencil you have. Measure it with a ruler and see if your guess was right.

Draw two dots on a piece of paper and measure the distance between them.

Guessing The Distance Between Two Places

Tai says: "We measured the length of the table with a ruler and the distance between two gateposts with a measuring tape. Now let us see how to measure a longer distance."

Dilip asks: "Shall we measure the distance between the school gate and our classroom?"

Meera says: "It will be a little difficult to measure with the tape."

Tai says: "We can measure the length of the path that you walk from the gate to the classroom."

Dilip asks: "Where will we find such a long tape?"

Tai says: "You walk that distance on foot, don't you?"

Dilip asks: "Of what use is that?"

Tai says: "Come, Meera. Walk 5 steps along this line. Now, Dilip, you measure the distance with the tape."

Dilip says: "The distance is 3 metres."

Tai says: "Meera, now walk from the school gate to the classroom. Tell us how many steps you take."

Meera says: "I took 95 steps till the classroom."

Tai says: "When we divide 95 by 5, the answer is 19. This means that 95 steps have 19 stages of 5 steps each. One stage of 5 steps is equal to 3 metres. Therefore, 19 stages make 19 × 3 = 57 metres."

Vivek says: "That means the distance from the gate to the classroom is about 57 metres."

Tai says: "You can use this method to measure the distance between your house and other places that you walk to, such as a friend's house, a shop or a garden nearby."

Teacher's Note

You can measure long distances by counting your steps. Walk 10 steps and measure with a tape. Then count total steps and multiply!

Exam Trick

Long distance = (total steps ÷ known steps) × measured distance. For example: If 5 steps = 3 m, then 95 steps = (95÷5) × 3 = 57 m.

Points to Remember

For long distances, count your steps and use a tape measure.
Divide total steps by the number of steps in the measured distance.
Multiply the answer by the measured distance in metres.
This method works for measuring distance to school, shops, or friends' houses.
Always count steps on flat ground for accuracy.

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