What are the multiples of 3 between 10 and 20?

The multiples of 3 between 10 and 20 are 12 and 15. To find the multiples of 3 in this range, you can start by dividing the endpoints by 3 and then finding the next whole number multiples within the range. In this case, 10 ÷ 3 = 3 with a remainder of 1, and 20 ÷ 3 = 6 with no remainder. So, the multiples of 3 between 10 and 20 are 3 x 4 = 12 and 3 x 5 = 15.