question_answer 13)

                Without any calculation, find the numbers which are surely not perfect squares. (i) 153                                    (ii) 257                                   (iii) 408                                  (iv) 441

Answer:

                (i) 153 The number 153 is surely not a perfect square because it ends in 3 whereas the square numbers end with 0, 1, 4, 5, 6 or 9. (ii) 257 The number 257 is surely not a perfect square because it ends in 7 whereas the square numbers end with 0, 1, 4, 5, 6 or 9. (iii) 408 The number 408 is surely not a perfect square because it ends in 8 whereas the square numbers end with 0, 1, 4, 5, 6 or 9. (iv) 441 The number may be a perfect square as the square numbers end with 0, 1, 4, 5, 6 or 9.