There are 12 sixth graders, 14 seventh graders,
and 7 eighth graders in a gym class. The gym
teacher randomly selects one student to collect
balls. In how many ways can choosing not a
seventh grader occur?

There are 12 sixth graders, 14 seventh graders,  and 7 eighth graders in a gym class.

The gym  teacher randomly selects one student to collect  balls, then the number of choosing that will not pick a seventh grader is:

N = number of six graders + number of eight graders = 12 + 7 = 19 (ways)

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