Everyone likes magic numbers, but not everyone knows that math numbers can be a lot of fun too. Whether to have fun with friends or to teach arithmetic to the class, this trick will get you talking.

## Steps

### Method 1 of 2: Finding out the age and number of the shoe

#### Step 1. Invite a volunteer to write down their age

Give him a piece of paper and tell him not to show you anything he's writing.

### Unfortunately, this math trick won't work for kids who are 99+ years old

#### Step 2. Ask him to multiply by five

Tell him that he should follow your instructions and do some quizzes. Start by asking him to multiply his age by 5.

- For example, if he is 42 years old, the count would be: 42 x 5 = 210.
- Suggest that he use a calculator if he thinks it necessary.

#### Step 3. Put a zero at the end of the answer

This Step will have the same result as a multiplication by ten. However, it's best to make things a little easier for the volunteer.

### Following this example, the number 210 would become 2100

#### Step 4. Add today's date

Tell the volunteer to add today's date. This part is just a distraction as the number added now will be subtracted later.

- For example, if it's March 15th, it would add 2100 + 15 = 2115.
- There is no need to involve month and year in the account.

#### Step 5. Duplicate the answer

The participant must multiply the previous answer by two. If necessary, allow him to use a calculator.

### 2115 x 2 = 4230

#### Step 6. Add shoe number

The guest must now write the shoe number and add it to the previous result.

### If his number is 40, the account will look like this: 4230 + 40 = 4270

#### Step 7. Multiply today by two and then subtract

To make it easier, do the multiplication yourself and then ask the guest to do the subtraction with your result.

### As it is March 15th in the example, do the math: 15 x 2 = 30 head. Then say, "Subtract 30 from your answer." The volunteer will then do the math: 4270 - 30 = 4240

#### Step 8. Reveal the magic to the audience

Ask the guest to read the answer aloud. The first part will correspond to his age; the second, the size of the shoe.

### Method 2 of 2: Learning the 1089 Trick

#### Step 1. Invite a friend who knows how to do math or who has a calculator

While the trick only involves addition and subtraction, some may end up getting confused by the instructions. For that reason, it's best to pick someone who is less likely to make a mistake.

#### Step 2. Write the number 1089 on a piece of paper without anyone seeing it

Announce that you will write a magic number on a piece of paper, write it down without showing anyone, and then fold it.

#### Step 3. Ask the guest to write a three-digit number

Tell him not to show it or say what number it is. Make it clear that none of the digits must be repeated.

- For example, he could choose: 481.
- If the participant is not very good at math, let them use a calculator.

#### Step 4. Ask them to write the number backwards

The same digits as the chosen number must be written on the bottom line, but in reverse.

### For example, 481 backwards is 184

#### Step 5. Transform into a subtraction account

There are now two numbers and the volunteer must subtract the smaller from the larger.

### That is: 481 - 184 = 297

#### Step 6. Put a zero at the beginning if the number has only two digits

Ask him if the number is two or three digits long and tell him not to say what it is. If it's a two-digit number only, tell it to add a 0 to the beginning.

### Following the example, the 297 has three digits, so there's no need to put a 0 in it. However, if your guest ended up with a 99, after adding the 0, he will get a 099

#### Step 7. Write this number backwards as well

Ask the participant to take the result and write it backwards. If it's a number ending in zero, ask him to write the zero as well.

### For example, the opposite of 297 is 792

#### Step 8. Add the last number with the opposite of it

The last count will be done by adding the last two numbers that were written.

### In the example, these would be: 792 + 297 = 1089

#### Step 9. Reveal the final result

Make the ad saying that you know the last number that was written. Unfold your piece of paper and show the number 1089 you had written on it.

### The answer will always be 1089. If the invitee ended up with another number, he or she missed the account during the process

## Tips

- Do not repeat the trick within the same group of people. For example, it won't be that impressive to guess 1089 more than once!
- The 1089 trick also works with most three-digit numbers, even if they contain repeated digits. However, it won't work if the number is the same when read backwards (like 161 and 282, for example) – to prevent this from happening, ask the guest for three different numbers.
- Never repeat a spell near the same person, as they could easily discover the secret and ruin your spell number next time. This kind of inconvenience can make any magician very embarrassed, especially in front of an audience or a group of friends.