Let the unknown number be x. Then (1/10)x = 0.002. To solve for x, multiply both sides by 1000 to remove the decimal fraction 0.002.
Then 1000(1/10)x = 1000(0.002), or 100x = 2. Dividing both sides by x returns
x=100/2, or x= 50 (answer)
All you do is multiply 15 and 6 you get 90. then divide 90 by 9 and you get 10.
