Subtraction

Subtraction is a fairly easy math subject to master and is one of those foundation skills that is crucial for being able to work all types of problems such as subtracting fractions and subtracting negative numbers.

In its simplest form, subtraction is simply taking away one or more numbers from another number. Subtracting numbers can also be referred to as subtracting intergers. When the top number is larger than the bottom number, the process is easy but things can get a little more complicated, just like when your best friend wants to date your sister.

Most everyone knows 2 – 2 = 0. Subtraction gets no more simpler than that. Learning to properly subtract is a math skill that will be needed for the rest of your life. If you don’t know how to subtract, you won’t have a clue if the cashier gave you back the right amount of change or if Uncle Sam deducted the right amount of taxes from your paycheck.

When it comes to subtraction problems that require borrowing, students sometimes have a little trouble. For instance, this is a sample problem that requires borrowing:

48

-29

As you can see, you cannot subtract 9 from 8. You will need to borrow one from the 4 so you can make the 8 an 18. When borrowing, you will make the 4 a 3.

318

48

-29

19

Borrowing is the only way to deal with a larger number being on top. It allows you to work out the problem correctly.

Once you have mastered the basics of subtraction, you can then move on to learning how to subtract fractions. This is an easy process if both the denominators (bottom numbers) are the same. For instance:

1 + 2 = 3

4   4     4

When a fraction has larger denominators, you will need to multiply to make them the same. For example:

1 –1 = You will multiply 1

2   6                                 2 X 3 to get 3

6

Now, the problem looks like this: 3 – 1 = 2

6   6     6

Subtracting mixed numbers is done in much the same way:

1 3 – 1 1 First, you will need to subtract the large numbers which equals 0.

4       4

Then, you will add the fraction portion which will equal 2

4

When subtracting negative numbers, you will need to use a number line to make the process easier.

If you are subtracting a positive number from a negative number you will start at the negative number and count backwards.

Using the number line makes subtracting negative numbers much easier than attempting to figure out the signs in your head.

When dealing with unlike signs, it is important to make sure you get the signs right because if you put the wrong sign in front of the right number, the problem is going to be wrong. Always check your signs twice before submitting your answer so you won’t end up with a negative when you need a positive.