I got to design a week-long mathemagic curriculum as part of a youth summer camp. The campers were all elementary school aged. Each day we learned one new trick. At the end of the week, some of our young mathemagicians performed what they learned for the whole camp and the parents.

As always, I'd love to hear what you think. You can contact me here.

As always, I'd love to hear what you think. You can contact me here.

**Magic Squares**

A magic square is a square filled with numbers in such a way that the numbers in each row and the numbers in each column all add up to the same total. The German artist Albrecht Dürer made use of these wonders in his Melancolia I. My students got to explore a taste of this ancient magic for themselves. After demonstrating the idea of a magic square, I asked the students to create their "own 3x3 magic square using the numbers 1 through 9 so that each row and each column adds to 15."

They were more creative with my instructions than I had anticipated! They came up with one of the standard solutions and a novel one using repeating numbers!

**What's Your Card?**

This trick requires exactly 27 playing cards. It doesn't matter which cards, as long as they're all different. Deal out all 27 cards in 9 rows & 3 columns, dealing across. Ask a volunteer to select a card. Have them show the card to the audience (without moving the card) while you turn your back. Ask the volunteer which column their card is in. Pick up all the cards, being careful to make the indicated column the second column picked up. Deal out the cards a second time, and again ask the volunteer which column their card is in. Pick up the cards, with that column as the second column picked up. Repeat this process one more time. On the fourth time dealing out the cards, their card will be card number 14, in the exact middle. (You can simplify the trick by using 9 cards and only asking which column twice.)

Can you figure out how the trick works?

**Transmogrifier**

A transmogrifier is an ancient magical device that turns one thing into another. Our transmogrifier takes the shape of a carefully constructed manilla folder. Using one is surprisingly easy. Can you figure out how it works?

**Take a Card, any Card...**

Before you learn this trick, you'll need a little refresher on your 5's multiplication table and a tip on multiplying by 2:

$1\times 5=5$
$2\times 5=10$ $3\times 5=15$ $4\times 5=20$ $5\times 5=25$ $6\times 5=30$ $7\times 5=35$ $8\times 5=40$ $9\times 5=45$ |
Multiplying a number by 2 is the same as adding that number to itself. So
$$17\times 2 = 17 + 17 = 34.$$ |

Once you have that down, you're ready to go. Take the cards A through 9 of any one suit and ask an audience member to select a card and not show you. Then have them perform the sequence of mathematical operations

- Multiply your number by 5.
- Add 7 to your result.
- Multiply your result by 2.
- Subtract 5 from your result.

**Mind Reader**

Take the cards A through 9 of a single suit, but hide the four inside your hat before the trick. (Every mathemagician wears a hat!) To start the trick, show the audience that you're holding some cards of varying values in your hand. Ask a volunteer to take a card and show it to the audience. Then instruct the volunteer to

- Multiply the number by 9;
- Add the digits of the result together;
- Subtract 5 from the result.

Now, tell them to concentrate on the final answer they arrived at (the result of the calculations, not the initial card). Then reveal that their mental energy has passed through the air and appeared inside your hat! How'd you do that?

Thanks for sharing in the joy of mathemagic. I'd love to know if you try any of these tricks out. You can contact me here.