# Common Math Mistakes!

From Huben's Wiki

Every year I see large numbers of easy mistakes to avoid.

- You can only cancel FACTORS of numerators and denominators.

- Parentheses mean that you need to perform operations on ALL terms inside the parentheses.
- For example, if you have (ab
^{2})^{3}, you need to cube the a and the b^{2}to get a^{3}b^{6}

- Don't forget to FOIL when you square an expression!
- (a + b)
^{2}= a^{2}+ 2ab + b^{2}

(sqrt(x) +3)^{2}!= x + 9