Multiplying and Dividing Integers

YouTube Playlist on Real Number Operations

Multiplying a negative number by a positive number will result in a negative number. And when multiplying two negative numbers the result will be positive. Be careful when simplifying 5(−6), the operation here is multiplication NOT subtraction so 5(−6) = −30. The rules for division are the same.

(Negative) x (Positive) = (Negative) 

Example: (−7)(+4) = −28

(Negative) x (Negative) = (Positive) 

Example: (−7)(−4) = +28

Also, zero times anything is zero.

Multiply or Divide.

Dividing by zero is undefined. What happens when you try to divide by zero on a calculator?

Zero and Division

Divide.

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Adding and Subtracting Integers

When first learning how to subtract real numbers, it is useful to think of this operation as adding opposite numbers. For example, 5 − 2 can be thought of as adding five with the opposite of two 5 + (−2). This may seem cumbersome, but sometimes it can help in understanding problems where you wish to subtract a negative number.

Two sequential negative signs, as seen above, is equivalent to addition. When adding two negative numbers the result will be negative. For example, if you spend $12.00 for a pair of shoes and $25.00 for a bag then you will owe $37.00 at checkout, −12 − 25 = −37.

Add and Subtract.

Video Examples on YouTube: