how are numbers represented in computers?

A computer can only process 1s and 0s, it can not process decimal numbers

For instance, a regular simple number like 5 ends up consuming a lot more memory than expected in plain Python— not too important when beginning with data analysis but with larger data sets you may need to specify the size of the integers for processing

Since computers can only process in binary, the size of an element to be represented and computed affects performance or speed. For that reason, numpy is a lot more efficient compared to standard python objects as you can modify size resulting in a faster performance