How would you go about solving a problem that like this: 75(125+81{they are both over 2}/2)?
Well they are both over 2 in that this is true
$$\frac{125}{2}+\frac{81}{2}=\frac{125+81}{2}$$
but you wouldn't do it like that
You would just add up the top and THEN divide by the bottom. It's much quicker.
