Last month, Mr. Douglas sold 36 of his books. This month, however, he only sold 8 books. What was the percent change in book sales from last month to this month?

Aregular hexagon rotates counterclockwise about its center. it turns through angles greater than 0° and less than or equal to 360°. at how many different angles will the hexagon map onto itself?

How to solve a simultaneous equation involved with fractions?

Find an bif a = {3, 6, 9, 12) and b = {2, 4, 6, 8, 10).