If your child is used to doing a worksheet or two, they will be able to do this quite easily, and will understand that they need to complete the task before they can move on to the next activity. Worksheets also help your child to learn how to follow instructions, and teach them about following rules.
Teaching reading and other language arts skills to preschool learners relies heavily on a concept known as modeling. Modeling merely means exposing young children to the types of behaviors and habits we want them to learn. Many parents and homeschooling educators employ this kind of instruction naturally, without giving it much thought.
This will include counting to ten, recognizing shapes and colors, being able to hold a pencil or crayon properly, and coloring in without scribbling. Basic math concepts such as recognizing patterns, understanding quantity and some simple addition and subtraction will be useful.
Since 3rd grade math relies on the concepts that were learned during kindergarten, first and second grades, don't be afraid to start your child at a lower level.