Unschooling is popular among homeschoolers, even among new "converts" who have seen the emotional damage done to their children by academic environments.
This natural learning or self-directed learning is even "endorsed" by a leading academic scholar .
But how can you learn math without being strictly being taught?
"If you never teach a stitch of math, in a mathematical culture your kids will learn heaps of it anyway. " [Here are 4 ideas to get started.]
And, it turns out that if you wait until a kid is ready and motivated, they can learn everything they need to know about math concepts from K through 12 to do well on an SAT in 30 hours according to David Albert.
Here's some good reading on the subject:
Have Fun. Learn Stuff. Grow.: Homeschooling and the Curriculum of Love
Wounded by School: Recapturing the Joy in Learning and Standing Up to Old School Culture
Unschooling Rules: 55 Ways to Unlearn What We Know About Schools and Rediscover Education
Teach Your Own: The John Holt Book Of Homeschooling
Feel-Bad Education: And Other Contrarian Essays on Children and Schooling
Punished by Rewards: The Trouble with Gold Stars, Incentive Plans, A's, Praise, and Other Bribes
The Schools Our Children Deserve: Moving Beyond Traditional Classrooms and "Tougher Standards"
The Unschooling Handbook : How to Use the Whole World As Your Child's Classroom