 ## Book: NCERT - Mathematics

### Chapter: 6. Squares and Square Roots

#### Subject: Maths - Class 8th

##### Q. No. 9 of Exercises 6.4

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9
##### There are 500 children in a school. For a P.T. drill they have to stand in such amanner that the number of rows is equal to number of columns. How many childrenwould be left out in this arrangement?

It is given in the question that there are 500 children in the school. They have to stand for a P.T. drill in such a way that the number of rows is equal to the number of columns.

The number of children who will be left out in this arrangement has to be calculated.

For this, the number which should be subtracted from 500 to make it a perfect square has to be calculated.

The square root of 500 can be calculated by long division method as follows:

 22 2 5̅ 0̅0̅-4 42 10084 16

The remainder is 16. It shows that the square of 22 is less than 500 by 16

Therefore, if we subtract 16 from 500, we will obtain a perfect square

Required perfect square = 500 - 16

= 484

Hence, the number of children who will be left out is 16

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