How To Add, Subtract, Multiply, and Divide Integers

Adding, Subtracting, Multiplying, and Dividing Integers...

First off, what's an integer?

An integer is a whole number that isn't a fraction, decimal, or percent. It's whole numbers, both negative and positive. It is an number complete itself.

Now, how do I add, subtract, multiply, or divide one?

I'll show you...

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Add:

Same Sign (+ and + or - and -): Add and keep the sign.

Ex:

• 3 + 3 = 6
• -9 + (-6) = -15

Different Sign (+ and - or - and +): Subtract the larger number by the smaller number. Then keep the sign of the larger number.

Ex:

• -9 + 8 = -1    (9 - 8 = 1, and 9 is the larger number, so it must be negative)
• 6 + -8 = -2    (8 - 6 = 2, and 8 is the larger number, so it must be negative)

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Subtract: Similar to Addition, Only a Couple Things Are Different

Same Sign: Subtract and keep the sign.

Ex:

• 8 - 4 = 4
• -10 - (-7) = -3

Different Sign: Keep the first number, switch to addition, and make the negative positive, or the positive negative (a.k.a. add the absolute value).

Ex:

• 8 - (-4) = 8 + 4 = 12, so the answer to 8 - (-4) is 12.
• -7 - 8 = -7 + (-8) = -15 so the answer to -7 + 8 is -15.

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Multiplication: Easier Than The Other Two

For multiplication, you don't need to really worry about signs, except the fact that it determines the answer. Don't know what I mean? Well, here's how you can tell if the answer's going to be negative or not...

• If both numbers are positive, the answer is going to be positive.
• If both numbers are negative, the answer is also positive (I'll explain an answer to why later, not really but still...)
• If one number is negative, the other positive, the answer is negative, doesn't matter which comes first.

If you're confused by the info above, think of these two sayings...

If you're multiplying with the same signs: Positive.

If you're multiplying with different signs: Negative.

But let's get to the easy part: actually multiplying multiplication...

You just multiply them. That simple.

Ex:

• 3 x 3 = 9 (since both numbers are positive, the answer is positive.)
• -6 x -9 = 54 (since both numbers are negative, the answer is positive.)
• -3 x 7= -21 (since one's positive, the other number negative, the answer is negative. Now get the sign thing? If not, consult your math teacher, because I have no other way to explain it to you. Your teacher might be able to help.)

That's it. Now isn't that easy?

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Division: Exactly like Multiplication

Now that you've revised multiplication, division shouldn't be that hard. It's the exact same thing as multiplication!!

                                                                           U

You just divide them, with the same sign rules as multiplication (same signs: positive, different signs: negative)

Ex:

• 8 / (<---- means division, I don't have the division sign) 2 = 4
• 6 / (-3) = -2
• -12 / (-2) = 6

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Well, there's integers. I hope you get it now. If you don't find some more help! It never hurts to find more help!

Sources: my teacher and notebook notes

--M Ann M

(The M's don't stand for math or math geek if you looked at my name you'd realize their my initials. My friend's made fun of that when I told them I started this, not saying any names...Carter, Justin, and Liv)