When a child is ready and willing, the basics like reading, writing, and math are quite easily learned. Traditional schooling forces children to learn these at the same age and at the same rate, often before a child is ready or interested. Thus, the process seems to be difficult and time-consuming. The fact is that we have seen children teach themselves to read, some at the age of 4 and some as late as 12, with absolutely no instruction. By age 13, you can’t tell the difference between the child who learned to read at 4 from the child who learned to read at 12. As for math, it has been proven over and over again that all of the math content from K thru grade 8 can be learned in just 6 weeks when the child is ready for it. Imagine all of that time saved for valuable play!
For a different perspective, watch the TED video Why Math Instruction Is Unnecessary.