#### notes

Here we have puzzeles in which letters take the place of digits in an arithmetic 'sum' and the problem is to find out which letter represents which digit; so it is like cracking a code.

Here are two rules we follow while doing such puzzles.

1. Each letter in the puzzle must stand for just one digit. Each digit must be represented by just one letter.

2. The first digit of a number cannot be zero.

For example : Find Q in the addition.

3 1 Q

+ 1 Q 3

____________

5 0 1

Solution : There is just one letter Q whose value we have to find. Study the addition in the ones column: from Q + 3, we get ‘1’, that is, a number whose ones digit is 1.

For this to happen, the digit Q should be 8. So the puzzle can be solved as shown below.

3 1 8

+ 1 8 3

__________

5 0 1

That is, Q = 8