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प्रश्न
Can you think of how to cut a postcard so that you can pass through it?

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उत्तर
Yes, I can pass through a postcard by making a loop from it.
The steps are given below:

Make lines on the postcard as shown in this figure.
Cut the postcard along the lines which touch its border.
This will make a loop as shown here.


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संबंधित प्रश्न
Just as precise measurements are necessary in science, it is equally important to be able to make rough estimates of quantities using rudimentary ideas and common observations. Think of ways by which you can estimate the following (where an estimate is difficult to obtain, try to get an upper bound on the quantity):
the number of strands of hair on your head
Just as precise measurements are necessary in science, it is equally important to be able to make rough estimates of quantities using rudimentary ideas and common observations. Think of ways by which you can estimate the following (where an estimate is difficult to obtain, try to get an upper bound on the quantity):-
the number of air molecules in your classroom.
What are the S.I. units of
- mass
- length
- time and
- temperature.
Write their names and symbols.
Match the following.
| Column A | Column B |
| (1) Length | a. kilogram |
| (2) Mass | b. cubic metre |
| (3) Area | c. metre |
| (4) Volume | d. square metre |
Fill in the blank.
In the ............ system, length is measured in centimetres.
Match the following.
| 1. | Length of the fore arm | metre |
| 2. | SI unit of length | second |
| 3. | Nano | 103 |
| 4. | SI Unit of time | 10–9 |
| 5. | Kilo | Cubit |
Fill in the following chart.
| Property | Definition | Basic Unit | Instrument used for measuring |
| Length | |||
| Mass | |||
| Volume | |||
| Time |

Difference in size 
Do this for yourself and find the difference.
The fencing of a square garden is 20 m in length. How long is one side of the garden?
You can play this game on the ground. Make two squares of one square meter each. Divide your class into two teams. Ready to play!
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There are two beautiful lakes near a village. People come for boating and picnics in both the lakes. The village Panchayat is worried that with the noise of the boats the birds will stop coming. The Panchayat wants motorboats in only one lake. The other lake will be saved for the birds to make their nests.

- How many cm is the length of the boundary of lake A in the drawing?(use thread to find out)
There are two beautiful lakes near a village. People come for boating and picnics in both the lakes. The village Panchayat is worried that with the noise of the boats the birds will stop coming. The Panchayat wants motorboats in only one lake. The other lake will be saved for the birds to make their nests.

- What is the length of the boundary of lake B in the drawing?
What are the materials needed to find the length of a banana?
The distance between one end and the other end is called ______.
The Unit used to measure length ______.
SI unit of electric current is ______.
How many astronomical units (A.U.) make 1 parsec?
Mars has approximately half of the earth’s diameter. When it is closest to the earth it is at about 1/2 A.U. from the earth. Calculate what size it will appear when seen through the same telescope.
According to the modern definition, what fraction of a second does light travel to define one metre?
Why is the speed of light used to define the metre?
