Math Magic Tricks

Start with a deck of cards. Before the trick, sneak a peek at the 10th card in the deck. Memorize it.

Now choose a volunteer. Ask him to choose a number between 10 and 20. Count out that number of cards — facedown — to create a smaller deck. Pick up the smaller deck.

Ask your volunteer to add the first and second digit of their number together. For instance, if he chose 12, the math equation would be 1 + 2 = 3.

Now, counting from the smaller deck, hand the volunteer the card that matches the new number. If he chose 12, give him the third card. Instruct him not to show it to you. (A little hint: it will be the card you memorized!)

While the volunteer is holding the card, ask if it’s the card you memorized from the deck. Feel free to use a little theater, like talking about the color or the suit — “Is it red? I’m sensing something sparkly...is it...is it a diamond? Is it a three of diamonds?”

Cue the applause!

This trick boils down to a math problem. While the equation seems random, the answer will always be 10, which ends up being the tenth card from the original deck. Reveal the secret to your child and have her try it out on another family member or a friend.

Begin this trick by telling your child you can read minds.

Ask them to think of any number. Any number will work, but you may want to warn your child that it may be easier for them if she chooses a small or even number.

Tell your child to double the number. Add 10. Divide it in half. Then, subtract the original number.

Look your child in the eye, make a face like you’re thinking really hard and then say, “Five!” If your child did their math properly, you have just guessed their number!

This trick is similar to the card trick in that magic is in the math — the answer will always be the same. Have your child try again with different numbers, writing out the math as she goes, to see how it works.

For the final trick, be prepared with a piece of paper and a pair of scissors. Start by telling the children that you will pass your body through a piece of paper. Pass the paper around and ask your audience to inspect it. It’s just a regular piece of paper, right?

When the paper is returned to you, fold it in half hamburger-style, so the short ends meet.

Cut a narrow rectangle from the side of the paper with the fold.

Cut alternating lines into the paper, start from the folded side. Don’t cut all the way through the paper.

Open the paper up — you will have a large hoop! Go ahead and step right on through.

This trick is a clever lesson in geometry. By cutting into the paper, you changed its perimeter. It’s also a great lesson to get children thinking creatively. What else can they do with a simple sheet of paper?