The Basics Are Easy to Teach and Learn
A child should be introduced to the phonetic alphabet and numbers from an early age -- no later than age 3. I assume your child is ready for the next step.
First, there is reading. Presumably, your child has gone through the McGuffey Primer or an equivalent. The next step is the McGuffey First Reader or its equivalent. Download it here:
Second, there is arithmetic. Somewhere along the path to calculus, the child must take over in most households. I say: the sooner, the better -- for the child and the parent.
With this program, you will be able to get your child well on the path to success in mathematics.
Ir you can buy used copies of the old Saxon math books in hardback, buy them. This site is for free instruction, but Saxon math may be what your child needs to excel in math. One size doesn't fit all.
For a free site that takes a child from 1 plus 1 = 2 all the way through calculus, visit Salman Khan's Khan Academy: www.KhanAcademy.org. You will see what a gifted teacher has done with free videos on YouTube. I suggest that you (and then your child) ignore any pop-up ads. Just click the X box to remove them.
I include all of the Ray's Arithmetic series. It goes from beginner through calculus. The first volume is Ray's New Primary Arithmetic. Download it here.