Five less than a number is at least -7 and at most 7.

Five less than a number is at least -7 and at most 7.

A number signifies an arbitrary variable, let's call it x.
Five less than a number: x - 5

Is at least -7 means greater than or equal to and at most 7 means less than or equal to, so we have a joint inequality:
-7 <= x - 5 <= 7