# How to fix a magic box

## This arithmetic trick is not difficult when you know how.

Magicians often contain acts that are not strictly magical, but allow the audience to feel that they have witnessed something impossible. Memory tricks, unusual scientific demonstrations, blindfolded chess games and fast mental math are examples.

Such successful tricks show that the artist has a better talent. In some cases, this is true – they can have an extraordinary memory or be grand master of chess. But in most cases, the artist uses the system. These systems can be simple or require tremendous skill – but they are still easier than doing a trick without any kind of system.

A popular mathematical trick is to make a “magic square”. This is a grid, usually 3 × 3 or 4 × 4, full of numbers. The numbers on each line correspond to the same number. Here’s an example: As you can see, all lines are no more than 15. Note that each number 1 to 9 is used once. If you could repeat the numbers, many magic squares would be trivially simple, like grid hero 1, which added 3!

## There’s nothing special about it.

Creating a magic square in front of an audience, if done correctly, can be an impressive demonstration of the obvious control of mathematics at a higher level. I’ll show you how to do this using a seemingly more × 4 grid.

This magic square is the 34th. This is the minimum amount with numbers 1-16. Hold this card so you can perform this trick whenever you want.

After dinner, you can change the conversation to numbers and bring out your business card. Explain the basic idea behind the magic square; each column and row is equal to the same amount. Let partners confirm this if they want to by adding columns and rows.

Tell them you’re trying to make them a magic box. Ask them to give you a double-digit number greater than 34.

Let’s say they give you number 87. Create your business card so you can see it and take out another piece of paper. Draw 4 × 4 grids. Subtrat number 34 from the destination number provided by guests. In our example, the target numbers are 87: 87 minus 34 = 53.53 are then divided by 4 in the nearest integer. That’s 13, and the rest is 1 (13 x 4 = 52; 52 + 1 = 53).

Remember number 13. We call it a quota and it’s one of two special numbers you need. Another specific figure is the quota plus the rest. In our case it is 14 (13 + 1).

Now you’re ready. Start by stealing your business card. Look at the top row. Add your first special number to column 1: 13 + 8 = 21 in column 8 of the map. Type this in the corresponding box in the new grid.

You will continue this way in all 16 places in the grid with four exceptions. When you get to the numbers 13, 14, 15, or 16 on the original card, add a special number and the rest.