Lucky Number 2013

Here's your nightly math! Just 5 quick minutes of number fun for kids and parents at home. Read a cool fun fact, followed by math riddles at different levels so everyone can jump in. Your kids will love you for it.

Lucky Number 2013

January 11, 2013

The year 2013 may have looked unlucky with that 13 on the end, but it turned out to be a great number.  It was the first year in a long time with 4 different digits. Also, the number 13 is prime, meaning it’s divisible only by itself and 1, and can’t be split into other equal-sized groups, so 2013 looks kind of yucky and prime also. But you can actually divide a lot of numbers into it.  Let’s do the math to find them!

Wee ones: Of the digits 2, 0, 1 and 3, which one is biggest?

Little kids: Numbers whose digits add up to a multiple of 3 are divisible by 3 (you can add 3 over and over to get that total). What do 2013’s digits add up to, and is it divisible by 3?  Bonus: How old were you in 2013, if you’d already been born?

Big kids: We hadn’t had a year with 4 different digits in a long time. When was the last one before that?  Bonus: Years with 4 different digits are actually pretty common.  Before 1987, what was the last year that repeated any digits?

 

 

 

Answers:
Wee ones: 3 is biggest.

Little kids: Yes! They add to 6, which is divisible 3 (=3 + 3).  Bonus: Different for everyone…take your age today, then subtract the number of years passed since 2013.  Example: if you’re doing this in 2016, 2013 was 3 years ago.

Big kids: 1987.  Bonus: 1981. Year 1982-1987 all had 4 different digits.

And thank you to Lynn Salvo at MathTree for the great 2013 factoids!

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About the Author

Laura Overdeck

Laura Overdeck

Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking while still in diapers, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.

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