Transcripts

Beth Norcross:
You just subtract 30 degrees from Fahrenheit, and you divide by 2. It'll get you pretty close. To go from Celsius to Fahrenheit, you double your Celsius temperature, and you add 30.

Beth Norcross, author of the book, Use Your Fingers, Use Your Toes, a book full of help for everyday math problems. Like, how do you figure a 15% tip quickly in your head?

Very easy. You've got a $50 bill for your family at dinner. If you want to leave a 15% tip, just move that decimal point one place over. You nuzzle it right between the 5 and the 0. So, 10% would be $5. (I think most people know that.) Take half of that, which is $2.50. Add those two things together - $7.50 is a 15% tip.

If you're going to lose weight, you need to know how many calories you burn in a day so you'll know how many calories you should eat in a day. Beth says all you do is take your weight and multiply it by 10. So, if you weigh 150 pounds, you burn about 1500 calories a day.

And percentages can be tough, but Beth has some help. Let's say you want to figure out that 8 is what percentage of 620?

Well, that's very easy. You take the number 8. Divide it by 620. Multiply it by 100, and you see that 8 is 1.29%, or about 1.3% of 620.

For transcripts and our free on-line newsletter, visit our website, www.somethingyoushouldknow.net. I'm Mike Carruthers, and that's Something You Should Know.