Amy bought 3 packages of party hats. Each package had 7 hats. She gave out 18 hats to friends. Which of these shows one way to find the number of hats Amy had left? Explain why you chose your answer.

a. Multiply 3 by 7 and then subtract 18.

b. Multiply 3 by 18 and then subtract 7.

c. Multiply 3 by 7 and then add 18.

d. Multiply 3 by 18 and then add 7.

a. Multiply 3 by 7 and then subtract 18.

b. Multiply 3 by 18 and then subtract 7.

c. Multiply 3 by 7 and then add 18.

d. Multiply 3 by 18 and then add 7.