This Problem Set is a part of the Lesson 11, Unit 2, Grade 7. Students understand the rules for multiplication of integers and that multiplying the absolute values of integers results in the absolute value of the product. The sign, or absolute value, of the product is positive if the factors have the same sign and negative if they have opposite signs. Students realize that (-1)(-1) = (1) and see that it can be proven mathematically using the distributive property and the additive inverse.