4. Cell Phone Salesperson
In math, eighth graders are introduced to the life-enriching slope intercept formula: y=mx+b. Despite the validity of many an eighth grader’s sneaking suspicions that the practical applications of this are in fact fewer than our overzealous teachers suggests, this is one that is especially prevalent in today’s sales sector. To determine the most economical cell phone plan, your eighth grade self can simply add the initial contract fee, product fee, etc. to the cost per month, and in this way compare plans for customers over the long term.
Of course this also works to determine things like how much a gym membership will ultimately cost, or determine your cab fare based on price per mile. You can even graph the cost of your journey as the cabbie drives you up and down the same back avenues of New York City, thus justifying your math teacher’s enthusiasm.