My ds5 is math crazy, so we've been doing math workbooks forever (he is odd - loves workbooks) .
My kids are odd too ;-)
I think G&T kids have more fun with quick calculations. Memorizing things is boring! I'm the same way (although when I was a kid, I was the kind of G&T where things just stuck in my head after I'd heard them once... I used to astound my parents, lol). Anyway. My kids are math monsters (DD9 is in the gifted math program at school), and they're not keen on facts either.
DS8 was doing negative numbers and fractions at 6, and now still struggles with memorized stuff. DD9 was adding, subtracting and multiplying at 3, and is only now just memorizing facts. My kids love the conceptual and are really put off by anything that's repetitive and bland.
I used to say the same thing "it would be faster to just remember, rather than recalculate" (such a simple concept - you think they'd get it, lol). Now I've let it be (for now, anyway - we'll see how they progress). Math facts are important, but my two kids are incredibly stubborn - sometimes it's easier and more effective to let them come to their own conclusions. My daughter seems to have finally decided that it's quicker to memorize, and so now she's doing it on her own. DS8 will come to this conclusion as well - likely faster on his own than if I get on his case too much.
