I recently got back from a presentation with math genius Mike Byster at Little Tor Elementary School in New City. After Mike showed the kids what he could do by multiplying, squaring and dividing a bunch of numbers in his head, he taught them a little trick for squaring certain three-digit numbers. This works for most three-digit number where the middle number is zero. Here’s an example:

You can square the number 106 in your head using these three steps:

1. Multiple the first two digits (1×1). Answer: 1

2. Multiple one of the last digits by 2 (6×2). Answer: 12

3. Multiple the last two numbers (6×6). Answer: 36

Put all three together and that’s your answer: 11,236

The second step changes, depending on the first digit. For 100s, you multiply by 2. For 200s, you multiply by 4. For 300s, you multiple by 6. And so on.

Now try it for 608. First person to e-mail me the answer without using a calculator gets bragging rights and I’ll post their name on the Hall Monitor blog (quite an honor, believe me). How will I know you didn’t use a calculator? I won’t, so it’s up to you to respect the honor system. Here’s my e-mail: bfrubin@lohud.com