there are many differences between -4 and 5, the main one being that regardless of positive or negative, 4 will always be even and 5 will always be odd. another difference is that 5 is a Fibonacci number while 4 is not. if you runs the sieve of eratostenes on a number grid, five will be included while four will not, since 1 *4 and 2*2 give four while only 1*5 gives five. there are more differences, more obvious ones being 4 is negative while 5 is positive, but that's the most strikingly obvious difference there is.
