# Do We Get a Grade For This?

### The Number System

Trista says that the difference between two negative numbers is always a positive number. She provides the reasoning below. Since -4 – (-9) = + 5 and -2 – (-3) =… More →

Alec used a number line to solve (-8) – (-7). A. Explain the mistake on Alec’s number line. B. Draw a number line that correctly shows (-8) – (-7), and… More →

Yanni used a number line to solve (-13) + (-9). A. Explain the mistake on Yanni’s number line. B. Draw a number line that correctly shows (-13) + (-9), and… More →

Samuel is writing a rule for adding numbers with unlike signs. He writes that when adding two numbers with unlike signs, the sum is always positive. He writes that he… More →

Samantha thinks that the sum of two negative numbers is always negative. Her  teacher asked her to use a number line to explain her reasoning. Draw a number line Samantha… More →

Mrs. Carl is teaching her class to add positive and negative integers. She asks her  students to write a rule to generalize what they have learned. Paulina says that when adding… More →

Skylar earned 56 points during the first 15 minutes of his video game. In the next 5 minutes, he lost 68 points. A. Use a number line to represent the problem… More →