I never owned the teaching guides, and we just headed into Singapore 2B when my kids were keen on the challenge (somewhere around ages 5 or 6). They did really well without having math facts memorized. If they'd still been counting 0-20 facts on their fingers I suppose it might have been frustratingly slow work for them -- though possibly not. Although my kids didn't have the facts memorized, they could work out 6+7 or 9+5 quickly and easily using a combination of strategies and that didn't impede them working ahead into the 2B material. Yes, facts like 6+7 and 9+13 were "review" for them ... but that didn't mean they'd memorized them, it just meant they could easily work them out in a way that left them enough mental energy to add other concepts and layers of complexity on top. One thing my kids have taught me: not to put a whole lot of stock in general pronouncements about what order and pace learning "should" be introduced to them. I go by what they seem happy to handle, not by the rules.
Mountain mama to three great kids and one great grown-up
I own Singapore 2a/b (where he placed in August, before we did any of the Fred books) but we've never used it. Although my son conceptually "got" addition, subtraction, multiplication and division, he didn't know his facts cold and that was apparently a critical factor before starting level 2.
I was worried about that as well since my DD didn't know all her math facts before starting 2a. I wasn't comfortable with "drilling" her because of her young age at the time so I just let it go (after asking a few btdt friends on other forums). Best decision I made...she is working along happily and steadily and recently started 3a. Her math facts are coming along too. I made up "math assignments" for her to complete. I print some pages with fun math fact practice and give her the week to complete the assignments. No pressure to get them done in a "drill" fashion and she is getting the practice with the facts.
I don't use the HiGs anymore but I do remember seeing that they think math facts should be hammered down before moving on.
I'm a huge Saxon fan personally. My dd5 is very gifted in math as well. When she had just turned 5, I was teaching her how to skip count. She's already learned how to count by 2's, 3's, 4's, 5's and 10's. So she asked me one day (while waiting on DH at Home Depot) to teach her how to count by 11's. I told her it was a bit tricky to count by 11's. I said it was pretty easy up to 99 and then it gets harder. But I thought, what the heck, I'll humor her. So I explained the concept to her. She then proceeded to count to 616 by 11's without skipping a beat, until dh was ready to go! I was shocked! Anyway, she's almost done with Saxon 2 and I'll just move her on to Saxon 3. If she keeps up the pace, she'll probably be in Algebra by 6th or 7th grade. It's worked great for my older children as well. I've used Horizons, BJUP, and Rod and Staff and prefer Saxon hands down. BTW, with dd5, I just skimmed through the material until I found a good placement for her, then started her working in earnest. No sense boring her to death with stuff she already knows just to say she completed the workbook. :)
Homeschooling Mama of 6 wonderful kids (14, 12, 10, 9, 7, and 5)
Homeschool Tracker - keeps me sane
My favorites: Teach Your Child to Read in 100 Easy Lessons, Saxon Math, Easy Grammar, Sonlight, Writing with Skill