My 8 year old son wanted to learn calculus the other day.  So, I thought he should study a little algebra first.  Here are a series of problems that are similar to the ones that I gave him:

x-5 = 10

He had no problem with that one

2X = 10

He thought that X needed to be a digit in a number that started with 2.  After I explained that it really was 2 times x = 10, he was able to figure it out.

Then combining the two operations:

2x -5 = 15

No problem with that one.

x^2 = 9

Needed a review on squares.  We only covered the positive answer to this problem.  I have not gotten into negative numbers with him yet.

x^2 + 4 = 20

This is the one that we are currently stuck on. 

Do you have suggestions on how to teach an eight year old algebra and calculus?  Leave them in the comments below.