What is three and one-eights minus one and seven-eights?

two and four eights is the answer for that question

3 1/8 - 1 7/8

3 1/8= 25/8

1 7/8= 15/8

25/8 - 15/8 = 10/8 = 1 2/8= 1 1/4

question: how many people can she serve?

answer: she can serve 16.66666667 people. so she can only give 16 people a complete serving.

question: does she have enough ice cream for her guests?

answer: no. explanation: she only has enough for 16 people to have a full serving. however, she can give a 17th person a partial serving.

so, converting firstly the mixed fractions to improper fractions and then "adding".