Last night, my fourth grader didn't want to do his homework. "Nothing I learn in school matters in the real world!" he complained. "Why will I ever need to know what 378 times 7 is?"

After explaining that the answer to that question wasn't important, but the ability to find it was, and ignoring the continued whining about homework, I received the following email from a reader (I changed the numbers to protect privacy):

Our company was recently bought out and my annual salary per my contract is $53,300, we used to get paid on a different pay period and therefore calculation. Now we are paid bi-weekly. I asked my HR person because I have a $202.40 discrepancy now. They are paying $28.91/hour instead of $29.02. The higher up has explained that it is because the money doesn't actually get paid all in the same year so it's 26.1 pay periods? It seems to me my hourly rate is $53,300/1,820 hours per year, how can it not be?

The answer to this question all revolves around math and problem-solving. No matter what work this person does, she needs math to answer her question.

Math seems to be hated and it shouldn't be. I once complained to my daughter's school principal that I thought the math curriculum was weak and she rolled her eyes and said, "Oh, are you one of those math people?"

Yes, yes, I am. But wait, you say, aren't you an HR person turned writer and speaker? Yes, yes, I am. And I wouldn't be where I am today without the ability to do math.

Now, I'm not saying that everyone needs to understand differential calculus. I couldn't do calculus now, as it's been close to 20 years since I've done it. But everyone needs to learn basic algebra.

What is algebra? It's problem-solving. In the real world, we have to figure out X all the time.

So, let's take a look at this employee's problem and figure it out. There aren't 52 weeks in a year; there are 52 weeks and 1 day in a year. Depending on your workweek, that can either result in 1,820 working hours per year (assuming a 35-hour workweek, which this person has), or 1,827 working hours per year. So, 7*29.02=$203.14, which explains the difference. (Why aren't the numbers exact? Rounding errors. We don't pay in partial pennies.)

But this also brings up a critical HR issue: How do you tell employees what their salaries are? Lots of people want to see an annual salary because we often think about money in those terms, but that's actually the worst way to tell someone their salary. (And incidentally, it's doubtful that this employee has an actual contract, as outside of unions those are quite rare in the United States, especially when you're not an executive.)

• Hourly employees: State salary as an hourly rate. Then there's no promise, implied or otherwise, of a total value. "You will be paid $29.02 per hour."
• Salaried Exempt employees: Exempt employees are paid by the pay period. If they are paid weekly, you list a weekly salary. If they are paid every two weeks, you list two weeks' worth of pay. If they are paid twice a month, you list whatever the annual salary is divided by 24. Employees who are paid every two weeks get 26 paychecks, compared to the 24 of a twice a month employee.

And, of course, you should have your employment attorney take a look at your offer letter template to make sure all everything is ship-shape. Local laws can vary, so you need someone familiar with those laws.

But back to the main point: We all need math or people can take advantage of us. And make sure your children's teachers and principals know that, yes, you are one of those math people who understand the critical nature of numbers in everyday life.