Rearrange the key caps of the 1 through 9 on a numeric keypad so that no cap is on its correct key, in such a manner that each of the three rows forms a 3-digit perfect square.
789
456
123
SQUARES:
There are only two that contain the digit 4 (324 and 784). Use a little trial and error and you'll get the answer.
324 --> 169 --> 578 (no arrangements work)
324 --> 196 (same thing)
324 --> 576 --> 189 (no arrangements work)
etc.
784 --> 169 --> 235 (no arrangements)
784 --> 196 (same thing)
784 --> 256 --> 139 (no arrangements)
784 --> 361 --> 529 yes!!
Answer:
19² = 361
23² = 529
28² = 784
solved by GOOGLE look-up
answer & spoiler
