...I will gladly help you maximize your ACT Math Score. Addition is like skip-counting: draw a number line 1,2,3,4,5,6,...etc. 2+4 starts at 2 and skips to the right by 4 and wound up with 6, after counts of 4 skips on that number line. Subtraction is reverse skip-counting, except we skip to the left. 3 - 2 starts at 3 and skips 2 to the left to give 1. (read more)