This topic covers the fundamentals of addition and subtraction when dealing with negative whole numbers, or integers. This topic heavily utilizes number lines to provide a conceptual foundation for the student.
These lessons provide a basis for handling negative numbers in arithmetic. Many important concepts are stated throughout these lessons.
This lesson is the first to introduce arithmetic with negative numbers. The lesson shows the student how adding a negative number involves moving to the left on a number line.
This lesson develops the idea that subtraction can be rewritten as addition by a negative number. The previous lesson is further developed here as the student sees the connection between subtraction and the addition of a negative number. A key concept that is explicitly stated is subtracting a number is the same as adding its opposite.
This lesson furthers the notion that we can rewrite subtraction as addition. The student learns the rule that subtracting by a positive number results in the difference being smaller than the minuend. Examples with a number line are used to allow the student to see this principle more concretely.
This lesson shows the student how rewriting subtraction as addition can be used to rewrite subtraction by a negative number into addition with a positive number. The student gets to watch examples that show this idea.