Teaching subtraction can be made easy by applying just a few simple ideas. Using a number line, showing how subtraction is the opposite of addition, using practical examples, and availing of on-line practice sheets, all contribute to making easy-to-follow lesson plans. Following each subtraction lesson plan up with reinforcement, and gradually building ability, will allow subtraction to be learned quickly and confidently.
Teaching Subtraction Using The Three Learning Styles
People learn using three types of approach. Each person tends to use one style more than another, and understanding the students main learning style is important. The three styles are:
- Audio - the student learns by hearing
- Visual - the student learns by seeing
- Kinesthetic - the student learns by doing
Students learn best when they use all three styles, with a bias to their preferred learning style. The teacher talking is the audio element, the number line allows the visual element to be used, and the objects allow the kinesthetic element to be utilized.
How To Explain Negative Numbers
The concept of a negative number is confusing to many students. It is easy for them to understand that they have three objects (e.g. counters). It is more difficult for them to understand when they have minus three (-3) counters. One effective way to explain negative numbers is the analogy that they "own" three counters, or "owe" three. Owning three counters means they have plus three (+3), but owing three counters means that they have minus three (-3). Emphasis should be put on the fact that if they "owe" three, or have minus three, then if they obtain three more then they just have zero. Many students respond well to the idea that it is so much easier to write "-3" than to write "owe 3". Another option is to treat +3 like 3 feet above water, and -3 as 3 feet below water.
Useful Tip To Remember When Teaching That Subtraction Is The Opposite of Addition
Two examples will be used here, to illustrate how easy it is to teach subtraction:
7 - 3 = ?, and
7 - (-3) = ?
Pointing at the number line, the teacher will explain that starting at number seven, 7 - 3 means start at number seven and move three places to the left. Then, starting with seven counters, count three of them and remove them from the group of seven. Then count what is left. One, two, three, four. This is the most common way to explain subtraction, but it is difficult to explain how to work out 7 - (-3). There is another method:
The teacher could ask the student "What needs to be added to three to get seven?" Starting at three on the number line, how many need to be added to reach seven gives the answer four. The advantage with this method is that it can be applied to the more difficult question of 7 - (-3). If the amended question is asked "what needs to be added to minus three to get seven, the student can use the number line and start at minus three, and can easily see that it takes ten steps to reach seven. Similarly, the student "owes" three, needs three to get to zero, and another seven to get to seven, so the total they need is seven plus three, or ten.
Practice Subtraction Using Fun Math Games Online
Having explained the basic principle of subtraction, the student needs some practice. There are many online subtraction examples, many using animated examples, that are either free or very cheap. With practice, the student will build confidence and competence in subtraction. One potential disadvantage of online math tuition is that the examples cannot be replicated at home using counters, but fortunately many online math classes allow the user to set the level appropriately, so that the student does not need so many counters.
Teaching Subtraction Summary
Subtraction, like most subjects, is best learned when all three learning modes (audio, visual, and kinesthetic) are used to teach. Teaching methods may be adapted to suit the learning style best suited to the student. Practice is essential, and many online math learning sites are available.
Teaching Subtraction References
The book " Two Plus Two is Not Five (Easy Methods to Learn Addition & Subtraction)" by Greenwald, Susan R., is a good beginners guide to subtraction. The article "Teaching subtraction" on this site deals with slightly more advanced subtraction where carry-over is needed.
Martin Bell - Martin holds a B.Sc. degree in chemical engineering, and an M.Sc. degree in electronics and computing. He has spent more than 25 years ...
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