Trick 1:

1. Get them to think of a 3-digit number.

2. Multiply it by 7, 11 and 13 and hey presto, you get twice that number.

For example:

1. Number is 123.

2. 123x7x11x13= 123 123!

Trick 2:

1. Think of any 3 digit number but each of the digits must be the same. E.g. 111, 222, 333

2. Add up the digits

3. Divide the 3 digit numbers with the result from step 2.

4. The answer is always 37

for example:

1. The 3 digit number is 111.

2. 1+1+1=3

3 111/3= *drum rolls* 37

Now try it yourself!