Math in Today’s Everyday Life

Every day now driving home and listening to the news, I try, like everyone else I imagine, to wrap my head around the kinds of numbers they’re throwing around. The scale of the numbers is incomprehensible. How meaningful is the difference between a billion and a trillion dollars? The best mental illustration I’ve heard recently—and many have repeated it—is that if you spent a million dollars every day from the day Jesus was born, you still wouldn’t have spent a trillion dollars. (I love a great headline: see “Numb and number”.)

So I was fascinated by a radio interview I heard yesterday with a science writer named K.C. Cole, whose premise is that our brains simply aren’t built to comprehend numbers this large. She talked about our natural tendency to focus on the difference in the number of digits between 2 numbers instead of the effect of multiplication. (OK this was my takeaway—it’s not precisely what she said.) For example 1,000,000 has twice the number of zeroes1,000 has. So our brains might tend to understand it as twice as much, rather than the fact that those 3 extra zeroes multiply the number by 1,000, which makes it quite a bit larger number.

Metapohrs Help us with the Math in our Daily Lives

She also suggested that we can use metaphors to train our brains to better comprehend differences in scale like this. She referenced the old story about doubling the grain of rice on each square of a chessboard, and by the 64th square you’d need more rice than is grown in the whole world. (By the way, we highlighted a cool book to help kids get this idea in a post a while back: One Grain of Rice: A Mathematical Folktale).

When I got home I looked it up the interview so I could share it. You can read what she actually said on the Marketplace radio show website.