I've gotten pretty good at deconstructing (a+b)c into ab + ac and working that out in my head - for example, 36 x 3 is (30+6) x 3 = (30 x 3) + (6 x 3) = 90 + 18

I've gotten pretty good at deconstructing (a+b)c into ab + ac and working that out in my head - for example, 36 x 3 is (30+6) x 3 = (30 x 3) + (6 x 3) = 90 + 18 = 108. Couldn't do it if I didn't remember the multiplication tables up to 10 though.