## Elementary Algebra

Last year, it was estimated there were 200 homeless people in the town. This year, it is estimated there will be 180 homeless people. To find the percentage change, we use the following formula: percentage change = $\frac{New\ amount\ -\ Original\ amount}{Original\ amount}$ $\times$ 100% The new amount is 180, while the original amount was 200. Substituting these values into the formula yields: percentage change = $\frac{180\ -\ 200}{200}$ $\times$ 100% percentage change = $\frac{-20}{200}$ $\times$ 100% percentage change = -0.1 $\times$ 100% percentage change = -10% Because the percentage change is a negative number, it is a percent decrease.