(i) 81

Since, here the given number has its unit place digit as 1, its square will end with the unit digit of the multiplication of unit place digit of the number with the unit place digit of the number itself.

(1 x 1 = 1) i.e., 1

(ii) 272

Since, here the given number has its unit's place digit as 2, its square will end with the unit digit of the multiplication of unit place digit of the number with the unit place digit of the number itself.

(2 x 2 = 4) i.e., 4

(iii) 799

Since the given number has its unit's place digit as 9, its square will end with the unit digit of the multiplication (9 x 9 = 81) i.e., 1

(iv) 3853

Since, here the given number has its unit's place digit as 3, its square will end with the unit digit of the multiplication of unit place digit of the number with the unit place digit of the number itself.

(3 x 3 = 9) i.e., 9

(v) 1234

Since, here the given number has its unit's place digit as 4, its square will end with the unit digit of the multiplication of unit place digit of the number with the unit place digit of the number itself.

(4 x 4 = 16) i.e., 6

(vi) 26387

Since, here the given number has its unit's place digit as 7, its square will end with the unit digit of the multiplication of unit place digit of the number with the unit place digit of the number itself.

(7 x 7 = 49) i.e., 9

(vii) 52698

Since, here the given number has its unit's place digit as 8, its square will end with the unit digit of the multiplication of unit place digit of the number with the unit place digit of the number itself.

(8 x 8 = 64) i.e., 4

(viii) 99880

Since the given number has its unit's place digit as 0.

Hence, its square will have two zeroes at the end. Therefore, the unit digit of the square of the given number is 0

(xi) 12796

Since, here the given number has its unit's place digit as 6, its square will end with the unit digit of the multiplication of unit place digit of the number with the unit place digit of the number itself.

(6 x 6 = 36) i.e., 6

(x) 55555

Since, here the given number has its unit's place digit as 5, its square will end with the unit digit of the multiplication of unit place digit of the number with the unit place digit of the number itself.

(5 x 5 = 25) i.e., 5