A big component of elementary math is memorization of the basic math facts. First grade involves a lot of addition, and even more memorization of the addition facts. There are several ways to do this, such as flashcards and having the students write tables of the math facts. Sometimes having them do oral drills is also helpful, and writing them on a chalkboard or dry erase board too. There is a multitude of online math games to reinforce the addition facts, and many kids find online flashcards much more fun than paper ones.
Now that subtraction facts also need to be memorized, many homeschooling families have already determined which methods work best for their children. This experience can help make the subtractions facts a bit less painful to memorize, although certainly some variation of the techniques never hurts. Multiplication is often introduced toward the end of second grade, and these facts will need to be memorized too.
Having the addition, subtraction, and multiplication tables committed to memory is extremely helpful and really a necessity before moving on to more complicated math. If you spend the time needed to master them, your student will excel in math because of it!