### Video Transcript

In the circles, write a multiple which belongs to each set. One has been done for you. Numbers from one to 99 multiple of 10 is 50. Numbers from 101 to 199 a multiple of 20. Numbers from 201 to 299 a multiple of 30. Numbers from 301 to 399 a multiple of 40.

The first one has been done for us. 50 is a multiple of 10 between one and 99. Next, we need to find a number which is a multiple of 20 between 101 and 199. To help us find the multiples of 20, we could use our knowledge of the two times table. 20 is 10 times bigger than two. Our multiples of two are two, four, six, eight, 10, 12, 14, 16, 18, 20, and so on. So the multiples of 20 between zero and 200 would be 20, 40, 60, 80, 100, 120, 140, 160, 180, 200.

We’re looking for the multiples of 20 between 101 and 199. So the first multiple we can write on our number line, which comes after 101 is 120, followed by 140, 160, and 180. Any of these numbers in pink could be our missing number. I’ve chosen 140 as the missing number. But we could choose any number from those listed: 120, 140, 160, or 180 because they are all multiples of 20 between 101 and 199.

Next, we’re looking for a number which is a multiple of 30 between 201 and 299. Because 30 is 10 times bigger than three, we could use our knowledge of the three times table to help us. Three, six, nine, 12, 15, 18, 21, 24, 27, and 30 are multiples of three. 210 is the first multiple of 30 between 201 and 299. 210 is also 10 times greater than 21, which we know is a multiple of three. The next multiple of 30 would be 240 then 270. Any of these three numbers would be the correct answer. I’ve chosen to write 270 as the answer. But 210 and 240 would also be correct.

Now, we just need to find a multiple of 40 between 301 and 399. And we can use multiples of four to help us find multiples of 40. 320 is the first multiple of 40 after 301 and 360 is the only multiple of 40 less than 399. So the answer could be 320 or 360. Both of these numbers are multiples of 40 between 301 and 399.

So the first missing number could be 140 which is a multiple of 20 between 101 and 199. The answer could also be 120, 160, or 180. 270 is a multiple of 30 between 201 and 299 so are 210 and 240. And 320 is a multiple of 40 between 301 and 399. And we could also have put 360 as a possible answer. We’ve written a multiple which belongs to each set.