The basics of subtraction lie in knowing simple number facts. Teaching your student how to count and order numbers will go a long way to helping him grasp the concept of subtraction. Use counting songs like "Ten in the Bed," in which the number of bears in the bed decreases. Start a math session by marching around the room counting as you go. Start by moving forwards and counting upwards, and then march backwards, counting backwards. Learning number sequences in this way will help special needs students to build confidence and develop a sound, secure knowledge base before moving on.
Special needs students respond well to having tangible objects to touch and maneuver. Provide brightly colored counters or try using plastic animals, dinosaurs or even small toy cars. If you can use objects that will appeal to your student, then she will be more enthusiastic and motivated. Count out a number of objects together. Take a certain amount away, counting as you do. Have your student then count how many objects are left. Extend this activity by counting out objects, then having your student close her eyes while you remove a certain amount. Have her open her eyes and count how many are left. Ask her how many you removed, and check her answer by counting those items that you took.
Help reinforce subtraction skills through the use of simple flashcards. On one side of the card write a subtraction question, for example "10 - 2." On the reverse, write the answer, in this case "8." Once made up, these cards can be used in a variety of ways. If working with an individual child or a small group, simply read out the question, or have your student read it. Then have her tell you the answer, checking the back of the card to see if she is correct. Alternatively, lay the cards out on the desk, question side up. Call out an answer and have your student find the card with the correct subtraction question.
Make sure that your special needs students have equal access to online math resources and computer software. Many special needs students find computer based math activities motivating and these activities are useful in reinforcing math ideas, giving the opportunity to practice and reinforce learning. Scholastic reports research stating that in a special needs class with an interactive whiteboard, students were on task for 81 percent of the time, compared to 58 percent of the time in a classroom without an interactive whiteboard. Try the scholastic website as a starting point for subtraction math games.