Skate World is a merchandising company that sells skateboards both at its retail store and its online store. Results for the most recent three months are shown below.

$\backslash$table$[[,$July,August,September$],[$Sales in units $.........................,4,000,4,500,5,000],[$Sales$,\frac{?}{\text{b}\text{a}\text{r}}($$$400,000),\frac{?}{\text{b}\text{a}\text{r}}($$$450,000),\frac{?}{\text{b}\text{a}\text{r}}($$$500,000)$