Why do we need to convert binary numbers into hexadecimal, octal and decimal?

Computer reads binary. Now my question is, what is the use of hexadecimal, octal and decimal? Do Computers understand or can read hexadecimal, octal and decimal? This question remains a mystery for me. Why memory locations use hexadecimal, it should be in binary right? Or is it because it is a binary and by time we read its memory location, the computer converts its memory location from binary into hexadecimal for us to make it readable?

• The popular computers use binary, but you can also build computers that use other numbering system like decimal – adrianN Jun 12 '16 at 13:08

Note that for a hexadecimal number, for example $7FC3$, in order to convert it to binary we need only take each hex digit and convert it to binary. Each hex digit (0-F) needs 4 binary digits to represent. $$7_{16} = (0111)_{2}$$ $$F_{16} = (1111)_{2}$$ $$C_{16} = (1100)_{2}$$ $$3_{16} = (0011)_{2}$$ This also works the other way round so its much easier for big binary numbers (that appear in memory addresses) to convert them into hex and manipulate them with this representations. If it was to convert them to decimal it would require more work (computing the corresponding polynomial) than this almost trivial algorithm.