(i) 1057

∵ The ending digit is 7 (which is not one of 0, 1, 4, 5, 6 or 9)

∴ 1057 cannot be a square number.

(ii) 23453

∵ The ending digit is 3 (which is not one of 0, 1, 4, 5, 6 and 9)

∴ 23453 cannot be a square number.

(iii) 7928

∵ The ending digit is 8 (which is not one of 0, 1, 4, 5, 6 and 9)

∴ 7928 cannot be a square number.

(iv) 222222

∵ The ending digit is 2 (which is not one of 0, 1, 4, 5, 6 or 9)

∴ 222222 cannot be a square number,

(v) 1069

∵ The ending digit is 9.

∴ It may or may not be a sqaure number.

Also,   30 x 30 = 900
         31 x 31 = 691
         32 x 32 = 1024
         33 x 33 = 1089

i.e. No natural number between 1024 and 1089 is a square number.

∴ 1069 cannot be a square number.

(vi) 2061

∵ The ending digit is 1

∴ It may or may not be a square number.

∵ 45 × 45 = 2025

and 46 × 46 = 2116

i.e. No natural number between 2025 and 2116 is a square number.

∴ 2061 is not a square number.

We can write many numbers which do not end with 0, 1, 4, 5, 6 or 9. (i.e. which are not square number). Five such numbers can be:

1234, 4312, 5678, 87543, 1002007.