You should know your square numbers as:
1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144 ....
But you should also know how to write them as:
12, 22, 32, 42, 52, 62, 72, 82, 92, 102, 112, 122....
You should know your cube numbers as:
1, 8, 27, 64, 125, 216, 343, 512, 729, 1000, 1331, 1728 ....
But you should also know how to write them as:
13, 23, 33, 43, 53, 63, 73, 83, 93, 103, 113, 123....