What will be the unit digit of the squares of the following numbers? 

(i) 81 (ii) 272 (iii) 799 

(iv) 3853 (v) 1234 (vi) 26387 

(vii) 52698 (viii) 99880 (ix) 12796 (x) 55555

The unit digit can be obtained by multiplying the unit digit of a chosen number with the same unit digit.

(i) 81 

The unit digit of 81 is 1, so $1\times 1 = 1$

So unit digit of the square of 81 is 1.

(ii) 272

The unit digit  of 272 is 2, so $2\times 2 = 4$

So the unit digit of square of 272 is 4.

(iii)

799

The unit digit  of 799 is 9, so $9\times 9 = 81$ whose unit digit is 1

So the unit digit of the square of 799 is 1.

(iv)

3853

The unit digit  of 3853 is 3, so $3\times 3 = 9$ 

So the unit digit of the square of 3853 is 9.

(v)

1234

The unit digit  of 1234 is 4, so $4\times 4 = 16$ whose unit digit is 6 

So the unit digit of the square of 1234 is 6.

(vi)

 26387 

The unit digit  of 26387 is 7, so $7\times 7 = 49$ whose unit digit is 9 

So the unit digit of the square of 26387 is 9.

(vii)

52698

The unit digit  of 52698 is 8, so $8\times 8 = 64$ whose unit digit is 4 

So the unit digit of the square of 52698 is 4.

(viii)

99880

The unit digit  of 99880 is 0, so $0\times 0 = 0$

So the unit digit of the square of 99880 is 0.

(ix)

 12796

The unit digit of 12796 is 6, so $6\times 6 = 36$ whose unit digit is 6 

So the unit digit of the square of 12796 is 6.

(x)

55555

The unit digit of 55555 is 5, so $5\times 5 = 25$ whose unit digit is 5 

So the unit digit of the square of 55555 is 5.