Question

MATHEMATICS
(iv)
EXERCISE 6.1
1. What will be the unit digit of the squares of the following numbers?
(1) 811
(ü) 272 e
4 (iii) 79971
(v) 1234 6
(vi) 26387
(vii) 52698 4 (vi
(ix) 12796
(x) 555555
2. The following numbers are obviously not perfect squares. Give reason
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378 not be last
(1) 1057
(i) 7928
(v) 64000
(vi) 89722 (vii) 222000
3. The squares of which of the following would be odd numbers?
(ii) 2826
(i) 7779​

Answer 1

1.

(i) 81= 1^2 = 1 So, unit digit will be 1

(ii) 272 = 2^2 = 4 So, unit digit will be 4

(iii) 799 = 9^2=81 So, unit digit will be 1

(iv) 3853 = 3^2=9 So, unit digit will be 9

(v) 1234 = 4^2=16 So, unit digit will be 6

(vi) 26387 = 7^2=49 So, unit digit will be 9

(vii) 52698 = 8^2=64 So, unit digit will be 4

(viii) 99880 = 0^2=0 So, unit digit will be 0

(ix) 12796 = 6^2=36 So, unit digit will be 6

(x) 55555 = 5^2=25 So, unit digit will be 5

2. No.s having 2,3,7,8 at unit place are not perfect squares, so, (i),(ii),(iii),(iv),(vi) are not perfect squares.

3. (i) 7779 is a odd number.