A: You’ve noticed that Grafting is, in fact, “the regular way to win Fluxx” by simply combining two (number) Keepers to make a larger number.

The Grafting Rule, however, is meant to make it possible to create numbers *for the specific purpose of subsequently using them in an equation* to reach the Goal number via calculation. The card’s exact wording is:

“Two Keepers can now be joined together to form a single two-digit number *for the purposes of Victory Rule calculations*.” (emphasis added)

So, no, you can’t just graft One and Three together to meet the Goal Unlucky. You could do it if you had an EXTRA One, though:

1 3 x 1 = 13