The concept of negative numbers is one many children find hard to grasp. Some don’t even want to try to understand this mystery of numbers that you cannot see using hard models. Below are a few tips you may be able to implement in order to teach your kids why negative numbers are important and also how to understand and use them properly.
First, help your child understand circumstances where negative numbers are used. Talk about owing money. If they are not familiar with that concept, teach them. Tell them that today you will give them one dollar and tomorrow you will give them one dollar. Sell them something today that costs two dollars. Explain that even though they only have one dollar, you will give them the toy (or whatever they are “buying”) and allow them to “owe” you the other dollar that they can pay tomorrow. Then explain that because they owe a dollar, it means that they are negative (or missing) one dollar.
When you are ready to teach the concept, start with something the child knows. Ask him or her to draw a number line for you that starts in the center of the page. After they have done this, say something like “Oh no, now this whole side of the page is blank! Let’s see what goes on that side of the number line.” Then ask them to draw out the line to the other side of the page but without numbers. Once that is finished explain that on the left side of the number zero is all of the negative numbers, meaning numbers smaller than zero.
At this point, you can refer back to the earlier lesson by asking them to remember how much money they owe you. If they don’t remember, feel free to go back to that concept, but if they remember quickly say, “Great. So because you owe me (or ‘are missing’) one dollar, that means you are negative one dollar.” Then on the first spot to the left of the zero write “-1”. Explain that the minus sign is a short way to write “negative”.
After that you can ask something like “So if owing (or missing) one dollar makes you negative one, what do you think owing/missing two dollars means?” You may need to lead the child slightly by suggesting “does it mean negative two?” And then allow the child to write -2 in the next spot on the number line.
Using this method it shouldn’t take long to understand that the more one owes (or is missing) the farther below zero they go. Once this is understood and the number line is filled out, you should make sure they understand that the numbers closest to the zero are actually bigger numbers than those farther from zero. Again, use your number line. Point to -4 and -1 and ask your child which is bigger or smaller. Continue until they have a solid understanding.
After an understanding with the above concept is reached, be sure to practice repeatedly over the next few days. If your child takes to the concept easily, you may begin teaching addition and subtraction using negatives. For this, think this way. If something good (positive) happens to a bad (negative) person is it good or bad? What is something bad (negative) happens to a good (positive person)? It’s bad, right? So if there is a + – or – + in an equation, it is negative. If something bad (negative) happens to a bad (negative) person, it is good (positive) so a – – in an equation means it is a positive. The wordy explanation may be a bit confusing, so here are a few examples. 5 + -3 could be rewritten as 5-3. 3 – – 5 could be written as 3 + 5. Also explain that the answer will have the same sign as the biggest numbers. So for 5 – 3, the answer will be positive whereas for 3 – 5 the answer would be negative.
Now, put the concept in action. Get the number line that you made together back in the open. Explain that negative or minus means move left while plus or positive means move to the right. Begin using some equations such as those above. If using 5 + -3 have your child put his or her finger on number five and move three numbers to the left. They will land on number two. Now have them place their finger on number three and move to the left five times. They will land on negative two.
While this may seem a lengthy way to teach the concept of negative numbers, it is one you will find useful. It should give your child a solid understanding of the purpose of negative numbers as well as how to use them. Above all, remember not to push your child too fast. If they seem stuck on step number one, stay there until they understand. It won’t be long before your child is ready to balance your checkbook (just hope it stays in the positive!).