1. Choose 3 digits from 1-9

2. Make all the 2 digit numbers you can from these (6)

3. Add the 3 original digits and divide them into the sum from step 2.

The answer is always '22'. I just can't understand why. Can you please help.

Another one related to this is it:

1. Choose a three digit number ensuring the first and third digit are differnt by at least two.

2. Make the reverse three digit number and subtract the smaller one from the larger of these.

3. Take this answer and reverse it and add these two 3 digit numbers .

eg:

643 - 346 = 297

297 + 792 = 1089

it doesn't matter what numbers are used, the results are alwasy the same. eg 22 or 1089