Tommy used benchmark fractions to estimate the sum of 1/5 + 3/7 as 1. Tommy's teacher said he was incorrect. Explain what error Tommy might have made and what tips you can give him to solve the problem correctly.

Dimitri used a coupon that saved him 80 percent, or $6.87. he paid $34.35 for the items. dimitri used a coupon that saved him 80 percent, or $27.48. he paid $34.35 for the items. dimitri used a coupon that saved him 80 percent, or $6.87. the price of the items before the discount was $34.35.dimitri used a coupon that saved him 80 percent, or $27.48. the price of the items before the discount was $34.35.