Squares and Square Roots-Class 8.

Chapter 6 of NCERT/CBSE Class 8 Mathematics is about Squares and Square roots. Here in this lesson you can find out practice problems for this chapter.

CBSE CLASS 8 MATHEMATICS.
Squares and Square Roots – Chapter 6/ Model Questions.
Fill in the blanks:

1. A perfect square does not end with —-, —-, —– or —- at unit’s place.
2. If a number has 1 or 9 in the unit’s place, then its square ends in —-
3. What will be the one’s digit in the square of 1234?
4. The number of zeroes in the square of 100 is —–
5. Square numbers can only have ——- number of zeros at the end.
   Answer the following:
6. What will be the unit digit of the squares of the following numbers?
   a) 5432
   b) 87960
7. The following numbers are obviously not perfect squares. Give reason.
   a) 2087
   b) 54000
8. State whether the square of given numbers is even or odd?
   a) 432
   B) 769
9. Find the square root of 121 by the method of repeated subtraction.
10. Express
    a) 25 as the sum of 5 odd numbers.
    b) 100 as the sum of 10 odd numbers.

ANSWERS:

1. 2, 3, 7 or 8.
2. 1
3. 6
4. 4
5. Even
6. a) 4
   b) 0
7. a) 2087 is not a perfect square, because it ends with 7. A perfect square does not end with 7 at unit’s place.
   b) 54000 is not a perfect square because square numbers can only have even number of zeros at the end.
8. a) The square of 432 is even.
   b) The square of 769 is odd.
9. To find the square root of 121:
   121 – 1 = 120
   120 – 3 = 117
   117 – 5 = 112
   112 – 7 = 105
   105 – 9 = 96
   96 – 11 = 85
   85 – 13 = 72
   72 – 15 = 57
   57 – 17 = 40
   40 – 19 = 21
   21 – 21 = 0
   From 121 we have subtracted successive odd numbers starting from 1 and obtained 0 at 11 th step. Therefore, square root of 121 is 11.
10. a) 1 + 3 + 5 + 7 + 9
    b) 1 + 3+ 5 +7 + 9+ 11 + 13 + 15 + 17 + 19.