### Barbies and Bicycles

In 1992 Mattel Toys got in trouble for releasing a talking Barbie doll that was randomly programmed to speak four lines from a 270 lines repertoire. Among these 270 lines were “I love shopping!”, “Wanna have a pizza party?” and ... “Math is tough.” Many years have passed since then and a lot has changed in our culture. But occasionally we still hear from our kids that math is tough and math is boring. And math departments of our universities still have more foreign-born students than local crop. (As you probably already discovered, I am one of those foreign weirdo math lovers.) Changing our culture's attitude toward math would take many more years. But if we want to prepare our kids for an interesting life in a global competitive world, let's start by presenting math for them as a toy and showing our excitement while playing with it.

A Try-It-at-Home-With-the-Kids Math Tip: Measure your street with a bicycle

You have probably seen some very serious people rolling a single wheel across the street. They surely could not be suspected as clowning around on a unicycle. They are measuring the length of a road in this very cool way, and you can try it too. Even if you do not have a unicycle. And even if you can’t ride a bicycle, as some of the people I know (sorry, mom). Just roll something with wheels next to you.

Get on your bicycle and count how many pedal rounds does it take to move from one side of the road to the next. Let’s say that it takes 12 pedal rotations to reach the end of your street.
Next, we need to find how much our bicycle travels with each pedal rotation. The easiest is to just mark with a chalk on a road the start and end point of a pedal rotation. Say, your bicycle moves 3 feet while you are doing one full pedal rotation. So, the length of your road is: 12 pedal rotations x 3 feet each = 36 feet.

Notice how many energetic pedal rotations your kid needs to make on his little bicycle to move these 36 feet. For your 12 rotations, he is probably making 36. So, he works 3 times harder than you, which explains why she is so tired after going around the block. Or, perhaps he was just bored and now that you can give him a real assignment of measuring the perimeter of the block, it will get surprisingly more interesting.

Latest Family Puzzle:
You are going for a business lunch with representatives of a company where many employees are known to be liars. Hungry and desperate to get an advice on what to order, you bluntly ask all three of them if they are liars.

The first one says, "All three of us are always telling the truth."
The second says, "No, only one of us is truthful."
The third answers, "The second man is telling the truth."

Well, whom can you trust from these three people?