Q: If we are playing with Plan C/Math Rules, and Grafting/Combine Digits comes into play, doesn’t that mean we can win without using math?

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

The Grafting/Combine Digits 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.

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