2. Multiplying Whole Numbers and Area Section 1.5

3. 4 + 4 + 4 + 4 + 4 = 5 x 4 = 20 5 fours factor product Multiplication is repeated addition with a different notation. 2 Martin-Gay, Prealgebra, 5ed

4. Multiplication Property of 0 The product of 0 and any number is 0. 9  0 = 0 0  6 = 0 3 Martin-Gay, Prealgebra, 5ed

5. Multiplication Property of 1 The product of 1 and any number is that same number. 9  1 = 9 1  6 = 6 4 Martin-Gay, Prealgebra, 5ed

6. Commutative Property of Multiplication Changing the order of two factors does not change their product. 6  3 = 18 and 3  6 = 18 5 Martin-Gay, Prealgebra, 5ed

7. Associative Property of Multiplication Changing the grouping of factors does not change their product. 5  ( 2  3) = 5  6 = 30 and (5  2)  3 = 10  3 = 30 6 Martin-Gay, Prealgebra, 5ed

8. Distributive Property Multiplication distributes over addition. 5(3 + 4) = 5  3 + 5  4 7 Martin-Gay, Prealgebra, 5ed

9. Area 1 square inch 11 11 5 inches 3 inches Area of a rectangle = length  width = (5 inches)(3 inches) = (5 inches)(3 inches) = 15 square inches = 15 square inches 8 Martin-Gay, Prealgebra, 5ed

10. Helpful Hint Remember that perimeter (distance around a plane figure) is measured in units. Area (space enclosed by a plane figure) is measured in square units. 5 inches 4 inches Rectangle 5 inches + 4 inches + 5 inches + 4 inches = 18 inches Perimeter = Area = (5 inches)(4 inches) = 20 square inches 9 Martin-Gay, Prealgebra, 5ed

11. There are several words or phrases that indicate the operation of multiplication. Some of these are as follows: Key Words ExamplesSymbols multiply multiply 4 by 3 4 3 4  3 product product of 2 and 5 2 2  5 times 7 times 6 7 7  6 10 Martin-Gay, Prealgebra, 5ed