Students develop the rules for multiplying and dividing signed numbers in this unit. They use the properties of operations and their previous understanding of multiplication as repeated addition to represent the multiplication of a negative number as repeated subtraction. From earlier grades, they recognize division as the inverse process of multiplication. Thus, signed number rules for division are consistent with those for multiplication, provided a divisor is not zero. Students extend integer rules to include the rational numbers and use properties of operations to perform rational number calculations without the use of a calculator.