Equation triangles make using equations for density, velocity, acceleration, and others much easier for students! They simply cover up the variable they are trying to find, and if the remaining two variables are next to each other, they multiply, and if they are above and below each other, they divide.
I use these in my 9th grade physical science class where I try to keep the focus on the science concepts and find tricks to help them through the math.
Included are triangles with equations for force, momentum, acceleration, velocity, power, work, and density.
These could easily be made smaller to be used in interactive notebooks.