Question

Each letter represents a different digit from 1 to 9. If R=4, what number does FOUR stand for

Answer 1

`R=8\Rightarrow O=4 \vee O=9`.

If
`O=4\Rightarrow T=2 \vee T=7`.
But none two three-digit numbers starting with 2 give a four digit number as a result when added up, therefore
`T=7 \Rightarrow F=1`

There's
`W` and
`U` left.

`W` can't be equal to 0, because this would mean also
`U=0` and each letter is supposed to represent a different digit.

`W` can't be equal 1, because
`F=1`.

`W` can't be equal 2, because
`U` would be equal 4, and already
`O=4`

`W=3` seems to be a fine digit, because then
`U=6` and 6 hasn't been used yet.
So
`FOUR=1468`.

It's possible that there are more solutions (for the rest values of
`W` and for
`O=9`, but I don't want to check for them :D
And sorry for my laconic explanation. I suck at this, especially in English :P