Calculator Tricks 3 By Brian Carruthers (Please see notes on slide 1)

The answer will always be 37 Think of a four-digit number and enter it twice into your calculator. For example:

I think that the number you have chosen is divisible by 137

Don’t you believe me? Why don’t you check this on your calculator?

Now divide your eight-digit number by your original four-digit number

Guess what? The answer is 73

How did I know?

Watch This: Entering a four-digit number twice ( ) is the same as multiplying it by (1234 x = ).

Because = 73 x 137: the eight-digit number will be divisible by 73, 137, and your original four-digit number.

What did you think of that? Isn’t Maths amazing?