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.

August 4, 2014

Today is the 4th day of the 8th month of 2014 – that’s a lot of fours, isn’t it? 8 can be divided evenly by 4, and so can 4, and 2014 has a 4 in it. So it’s a great time to talk about this very cool number. For one thing, the English spelling of “four” has 4 letters, and no other number does that: no other number has its own number of letters (try to find one). And here’s a wilder one: to what number do all number words reduce? 4. Try it: how many letters does “ten” have? (three.) And how many letter does “Three” have? (Five.). How many letters does “five” have? Four! Now try it with 6: How many letters does six have? It has three, and you end up right where you were before. This will happen with any starting number, whether it’s 12 or 25 or 5,783. Even zero and pi work out. While you’re testing that out, here are some fun 4 facts to celebrate the day.

*Wee ones:* Can you count to 4? If you can, can you count to 8?

*Little kids:* How many different pairs of numbers add up to 4? (Hint if needed: Don’t forget zero, and don’t worry about the order of numbers.) *Bonus:* If you start with 4 and keep adding 4 over and over, what’s the next number that ends in a 4?

*Big kids:* Here’s a cool speed trick to show off: multiplying by 25 is the same as dividing by 4 and then adding two zeros on the end (because that’s the same as multiplying by 100 over 4, which is 25). So, real quick: what’s 16 times 25? *Bonus:* What’s 80 times 25?

Answers:

*Wee ones:* 1, 2, 3, 4, then 5, 6, 7, 8.

*Little kids:* 3 pairs: 0+4, 1+3, and 2+2. *Bonus:* 24, which is 4×6.

*Big kids:* 400. *Bonus:* 2,000!

And a big thank-you to Patrick I. for these fun facts!

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 before she could walk, 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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