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Multiplication with Negative Numbers

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From YouTube, produced by Lawrence Perez/Candice Jhu
 
This video starts with a note that the student should watch the video on absolute numbers. The meaning of multiplication is reviewed, it is repeated addtion. Using a number line they explain how positive and negative numbers impact the equation. 3 x 1 = 1 + 1 + 1 = 3, -1 x 3 = -1 + -1 + -3. They show it this way to show that a positive times a positive is always a positive and a negative times a positive will always be negative. By the commutative property then a positive times a negative is negative. Then some examples are done. They also show another rule: multiplying a number by -1 is the same as taking the opposite of the number. They then go through a few examples. Then they go through a negative number times a negative number. The rule they discover is: negative times a negative number equals a positive number. Some examples are done. Video is good quality and good for all students as review or initial learning of the concept. There are English captions at the bottom.
 
Ages: 10 - 16 License: Proprietary Owner: Lawrence Perez Found by Barb
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