The Way You Learned Math Is So Old School If you're a parent of a certain age, your kids' homework can be confounding. Blame it on changes in the way children are taught math these days — which can make you feel like you're not very good with numbers.
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# The Way You Learned Math Is So Old School

#### The Way You Learned Math Is So Old School

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Arithmetic is the gateway to algebra, Weekend Edition Math Guy Keith Devlin says. iStockphoto.com hide caption

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### The Way We Used To Multiply

The old way to multiply required a student to add the products of 36 x 4 and 36 x 2. The trick is to add that 0 at the end of the second product.

Your fifth-grader asks you for help with the day's math homework. The assignment: Create a "stem-and-leaf" plot of the birthdays of each student in the class and use it to determine if one month has more birthdays than the rest, and if so, which month? Do you:

a) Stare blankly

c) Say, "Why do you need to know that?"

d) Shrug and say, "I must have been sick the day they taught that in math class."

If you're a parent of a certain age, your kids' homework can be confounding. Blame it on changes in the way children are taught math nowadays — which can make you feel like you're not very good with numbers.

Well, our math guy, Keith Devlin, who is very good at math, tells Weekend Edition Saturday host Scott Simon that there's a reason elementary schools are teaching arithmetic in a new way.