the-rules-for-multiplying-integers-and-why-they-work-incl-negative-times-negative-and-exponents

A basic lesson on multiplying integers for pre-algebra or 7th grade math. I explain where we get the various rules for the SIGNS in integer multiplication, and give examples.

For example, a positive times a negative integer can be modeled with counters. 4 x (-6) would be four groups of six negatives. The answer is negative (-24).

A positive times a negative can be "turned around" because multiplication is commutative, so it also gives a negative answer.

I present the situation with negative times a negative with a PATTERN. If we follow the pattern in a logical manner, we find that a negative times a negative MUST be positive.

In the end, we look at multiplying several integers plus powers with negative bases, such as (-2)^5 or (-10)^8, and notice that when the exponent is ODD, the answer is negative, and when the exponent is EVEN, the answer is positive.

If you like the video, subscribe to my channel. :) Thanks in advance!

Learn more pre-algebra with Math Mammoth Grade 7 Curriculum at http://www.mathmammoth.com/complete/grade_7.php - available as an instant download and as printed copies. Check out the free samples also!

Tagged under: Integer,Mathematics (Field Of Study),Multiplication,Exponentiation (Literature Subject),multiplying integers,rules,Negative Number,negative times negative,positive,negative,multiplication integers

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