• 2 months ago
Transcript
00:00This is Rohit, he has a ruler in his hand.
00:06I think he is going to his mother to ask her something.
00:12Come, let's follow him.
00:15I feel we will be able to learn about length with him today.
00:22Mom, isn't a ruler also called a scale?
00:27Yes dear, a ruler is also called a scale.
00:34And what are these markings on it?
00:37These markings indicate the centimetres.
00:42We can measure the length of any object in centimetres.
00:50Here, the numbers 0 to 15 show 0 to 15 centimetres.
01:01Hmm, so these show the centimetres.
01:05But how do we measure the length with this?
01:09Come, let me explain.
01:12We measure the length from the 0 mark by counting numbers from 0 to 15.
01:24We read the length as 1 centimetre, 2 centimetres, 3 centimetres and so on.
01:36To write centimetre, we use its short form that is cm.
01:46Mom, can I measure the length of this pencil with this ruler?
01:52Yes of course, let me show you how.
01:56Keep the pencil on the table.
01:59Keep the ruler beside it.
02:03You have to take care that one end of the pencil coincides with the 0 mark of the ruler.
02:13Now look at the other end of the pencil.
02:18Can you tell me which number it coincides with on the ruler?
02:2414, so its length is 14 centimetres.
02:30Correct! Now let us measure this eraser.
02:36I think it is 4 centimetres.
02:40Correct! So now you know how to measure the length of small objects.
02:48But longer objects cannot be measured with this small ruler.
02:56They are measured in a bigger unit called metre.
03:02Metre is written in short as m.
03:08One metre is equal to 100 centimetres.
03:16Would you like to convert some metres into centimetres?
03:21It is very easy.
03:23Yes!
03:24Now as I said one metre is equal to 100 centimetres.
03:33So to convert metres into centimetres we have to multiply the metres by 100.
03:46So for example to convert 2 metres into centimetres we have to multiply 2 into 100 which is equal to 200 centimetres.
04:05I got it!
04:07So if I want to convert 5 metres into centimetres I have to multiply 5 by 100 which is equal to 500 centimetres.
04:22Correct! Now come with me.
04:26I have to buy some ribbons and pennant strings.
04:32I think I will be able to teach you how to add and subtract metres and centimetres while buying them.
04:44Whoopee! I am ready. Let's go.
04:48So friends, you too get ready.
04:52We will go shopping with Rohit and his mother in the next lesson
04:57to learn how to add and subtract metres and centimetres.
05:03Bye for now!