Use reasoning to lead to the answer of the following question:
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?

7
Jen scored 20 + 10 = 30 on the exam.

Sammy scored two less, so his score was30 - 2 = 28.

Thus, Sammy made 35 - 28 = 7 mistakes.

.

So, the final answer is 7