I am a High School Science Teacher and we deal with a lot of word problems that contain many variables that could fit into many different equations. Here is how I break down the content step by step for my students.
A box is accelerating across a frictionless surface. It is being pushed with 75 newtons of force and the has a mass of 10 kilograms. What is the magnitude of the box's acceleration?
1) You want to identify and label all variables presented to you in the problem.
Ex: F = 75 N, m = 10 kg
2) Identify and Label the Variable the question is asking you to find.
Ex: a = ?
3) List possible known equations that have the variable you need to solve for.
Ex: a = v/t
F = ma
4) Choose the equation that has variables that are known from the problem.
Ex: We know m and F so equation F = ma is the equation I would choose.
5) Plug in information that is known and solve for the unknown variable.
Ex: 75 N = 10 kg (a) divide by 10 kg on both sides of the equal sign and a = 7.5 m/s2
Following these 5 easy steps really helps my students keep everything in order and solve for the true answer to the question being asked.
Hope this helps and if additional help is needed I would be happy to assist in any science class.