permutation/combination There are six cards with numbers written on them: $1, 2, 3, 4, 5, 6$ .
Two of them are drawn at at time and put together to form fractions, e.g. $\dfrac45$
How many proper fractions can be formed?
What is correct equation to solve this type of questions?
thanks

If you think of all the possible fractions, exactly half of them will be proper (since you're always drawing cards of two different values), so there are $6 \times 5 \times \frac12$ possibilities.
