Which of the following descriptions would be a good way to think about multiplying 15 times 22?
A
Round the 22 to 20. Think of the 20 as 2 times 10. Multiply the 15 times 2. Multiply your answer times 10. Add about 10 more to your answer since you rounded down earlier.
B
Multiply 22 times 10, and then add half of that much again to your answer.
C
Break the 15 into 10 + 5 and the 22 into 20 + 2. Multiply the 10 times the 20 and the 5 times the 2. Add the two products together.
D
Multiply 15 times 20, and add 2 more 20’s.