Khan Academy
Khan Academy: Adding Negative Numbers on the Number Line
Practice matching number line diagrams to addition expressions involving negative numbers. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Goodwill
Gcf Global: What Are Negative Numbers?
Learn all about negative numbers, which are any number less than zero.
National Council of Teachers of Mathematics
Nctm: Illuminations: Volt Meter
As you put the different type of batteries on the volt meter pay attention to the voltage equations in the table. See how positive and negative numbers interact.
Cool Math
Coolmath: Coolmath4kids: Orbit Integers
Add positive and negative numbers in this multiplayer space race!