Multiplying Integers Concept 7

Things you need to know… A “negative” sign and a “minus” sign mean the same thing A “negative” sign and a “minus” sign mean “change direction” Always assume your moving in a positive direction unless you are told to “change direction”

Example: 8 A positive 8 means go forward eight

Example: A “negative” 8 means “change direction” and go eight

How to Multiply Integers Using colored beans

Things you need to know White means a positive answer Shaded means a negative answer To “change direction” simply flip the bean Always assume you are moving in a positive direction until you are told to “change direction”

3 x 4

12

-3 x 4

-12

3 x -4

-12

-3 x -4

-12

-3 x -4 12

Fast Way An even number of negative signs in a problem means the solution is positive An odd number of negative signs in a problem means the solution is negative 7 x -3

Fast Way An even number of negative signs in a problem means the solution is positive An odd number of negative signs in a problem means the solution is negative 7 x -3 This problem has one negative One is an odd number Therefore, the solution is negative Now, just multiply the numbers!

Fast Way An even number of negative signs in a problem means the solution is positive An odd number of negative signs in a problem means the solution is negative 7 x -3 This problem has one negative One is an odd number Therefore, the solution is negative Now, just multiply the numbers! -21

Fast Way An even number of negative signs in a problem means the solution is positive An odd number of negative signs in a problem means the solution is negative -4 x -5

Fast Way An even number of negative signs in a problem means the solution is positive An odd number of negative signs in a problem means the solution is negative -4 x -5 This problem has two negatives Two is an even number Therefore, the solution is positive Now, just multiply the numbers!

Fast Way An even number of negative signs in a problem means the solution is positive An odd number of negative signs in a problem means the solution is negative -4 x -5 This problem has two negatives Two is an even number Therefore, the solution is positive Now, just multiply the numbers! 20

Fast Way An even number of negative signs in a problem means the solution is positive An odd number of negative signs in a problem means the solution is negative -2 x -3 x -1

Fast Way An even number of negative signs in a problem means the solution is positive An odd number of negative signs in a problem means the solution is negative -2 x -3 x -1 This problem has three negatives Three is an odd number Therefore, the solution is negative Now, just multiply the numbers!

Fast Way An even number of negative signs in a problem means the solution is positive An odd number of negative signs in a problem means the solution is negative -2 x -3 x -1 This problem has three negatives Three is an odd number Therefore, the solution is negative Now, just multiply the numbers! -6