Chapter 1 - Whole Numbers - 1.9 Reading Pictographs, Bar Graphs and Line Graphs - 1.9 Exercises - Page 86: 7

10,500 stores

From the chart, we observe that Dollar General has 22 symbols while Costco only has one. The difference in numbers of symbols is: $$ =22-1=21$$ Since each symbol represents 500 stores, the difference in the number of stores is: $$ =21\cdot500 =10,500$$