Bryan's score on a math exam is 20. Jen scored 10 more than Bryan while Sammy scored 2 fewer than Jen. If the math exam has 35 points in all, how many mistakes did Sammy make?
Jen scored 20 + 10 = <T>add(20, 10)=30 on the exam.
Sammy scored two less, so his score was30 - 2 = <T>subtract(30, 2)=28
Thus, Sammy made 35 - 28 = <T>subtract(35, 28)=7 mistakes.
