Let's call the number "n"if we write in an equation what you said it's like this: n*2+4-n-3=n +1. First i will move all the "n"s to the left and all the numbers to the rightn*2-n-n=1+3-4 which is… .0=0 this means that for EVERY number, if you double it, add four, subtract three, you will get this number plus one.