Can you believe this is someone’s bedroom? A kid named AJ loves the video game Super Mario so much, her dad painted her room to look like it! One wall shows Mario and other characters; another has bricks for them to climb. Even the clouds are made of teeny white and blue squares. It’s a good thing nothing on the wall is moving, or AJ would never fall asleep. super

*Wee ones:* What shape are the bricks on the wall? How many sides does each one have?

*Little kids:* If they used stickers for Mario and Bowser, then painted 3 other characters, how many characters have they made so far? *Bonus:* If it took 4 hours to paint a character starting at 2:00 pm, at what time did they finish?

*Big kids:* A grown-up friend painted the sky to help out. If the sky used 5 cans of blue paint per wall, how many cans did they need for all 4 walls? *Bonus:* If that stack of bricks has 1 in the first row, 2 in the second, and so on down to 8 at the bottom, how many bricks are there? (See if you can get it without counting one by one!)

*The (blue) sky’s the limit:* What if the stack of bricks had 10 rows, with 10 in the bottom row? How many bricks would there be? See if you can spot the shortcut for the total number in these stacks…(Hint if needed: How many are in the top row and bottom row together? Now how about the second row and second-to-last row together? and so on…)

__Answers:__

*Wee ones:* Squares, with 4 sides each.

*Little kids:* 5 characters. *Bonus:* At 6:00 pm.

*Big kids:* 20 cans. *Bonus:* 36 bricks.

*The sky’s the limit:* 55 bricks. These are the “triangle numbers,” where each row has 1 more than the one above it. The total number will be the number in the bottom row, times the number 1 bigger than that, then cut in half. So for 8 in the bottom row, it was 8 x 9 then cut in half, which is 72/2 or 36. For 10, it’s 10 x 11 cut in half, which is 55. That’s because the top and bottom row (10+1) make 11, and the second and second-to-last (9+2) also add to 11…you end up adding 5 sets of 11.

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.