With this I learned how to add and subtract. To learn fractions my teachers had a wodden apple that was cut up into four pieces and a wooden pear that was cut in half. From this I learned the concept of quarters and halves. I had the worst handwriting in class. Many autistic children have problems with motor control in their hands.
Neat handwriting is sometimes very hard.
This can totally frustrate the child. To reduce frustration and help the child to enjoy, let him type on the computer. Typing is often much easier. Some autistic children will learn reading more easily with phonics, and others will learn best by memorizing whole words. I learned with phonics.