Math in English – based on Singapore Math, this is the site to use if you need extra resources for that curriculum. Web based plus printable options.
From Simple Homeschool blog, 50 books for elementary and middle school.
Beast Academy – I haven’t used this but know quite a few people who do and absolutely love it. Great program for grades 2-5 from the makers of The Art of Problem Solving. Here’s a guide to what to buy.
Singapore Math – what we use since it’s what our previous school used. I think I’ll switch to Beast Academy at some point. You can find Singapore math books at used book stores – they can be expensive new from their website. Do the diagnostics test online to figure out level, since that part can be confusing.
Self-paced online multiplication course. You can pay what you like – it’s set at $30 but you can dial the amount up and down. No pre-reqs needed and it can be adapted for kids from kindergarten up to high school.
Life of Fred – buy at Educents, or get them secondhand – they hold up well, so they’re passed around a lot among families. There’s a Life of Fred sale going on as of 3/18/2018. Overview of the Life of Fred series will help understand which books for which ages.
It was easy for my 6 year old but it’s good to start this series at the beginning (it’s a bit odd and tells a story that needs to start from the beginning). If the first book is too simple, just read it like a story book until you get to the correct level.
Middle school math
Art of Problem Solving (AOPS) – This is the Pre-Algebra book that takes the prize.
Post-Algebra II math:
Check out this blog for some math.