Multiplying and Dividing Signed Integers

Multiplying and Dividing Signed Integers

Positive * Positive When we multiply or divide two integers, the sign rules are different than when we add or subtract signed numbers. When we multiply or divide two positive integers, the solution is positive. 7 6 42 12 3 4 2 9 18 16 8 2 20 1 20 8 8 1

Negative * Negative When we multiply or divide two negative integers, the solution is also positive. (-7) (-6) 42 (-12) (-3) 4 (-2) (-9) 18 (-16) (-8) 2 (-20) (-1) 20 (-8) (-8) 1

Positive * Negative When we multiply or divide one positive & one negative integer, the solution is always negative, regardless of which is larger or which is written first. (-7) 6 - 42 12 (-3) - 4 2 (-9) -18 (-16) 8 -2 20 (-1) -20 (-8) 8 -1

Summary Adding Integers: Positive Positive Positive Negative Negative Negative Positive Negative Sign of Larger # Subtracting Integers: Keep - Change - Change Multiplying/Dividing Integers: Positive Positive Positive Negative Negative Positive Positive Negative Negative

You Try It! Multiply or divide. 1. (-10) 3 2. (-4) (-3) 3. 7 (-2) 4. 5 (-2) 5. (-18) (-3) 6. (-20) 2 Simplify each expression. 7. (3)(-5x) 8. (-2)(-3y) 9. (-1)(7x) 10. (10)(-5c)

Solutions 1. (-10) 3 -30 2. (-4) (-3) 12 -14 3. 7 (-2) -10 4. 5 (-2) 6 5. (-18) (-3) 6. (-20) 2 -10

Solutions 7. (3)(-5x) -15x 8. (-2)(-3y) 6y -7x 9. (-1)(7x) 10. (10)(-5c) -50c