Many students struggle with solving multi-step equations and conversion factors. If you follow the basic steps, you will be less likely to make mistakes.
1. Combine like terms
2. Isolate the terms that contain the variable you wish to solve for (usually done with addition/subtraction)
3. Isolate the variable you wish to solve for (usually done with multiplication/division)
4. Substitute your answer into the original equation and check that it works
Converting with Measurements:
1. Set the problem up as a ratio -- = --
2. Put the conversion factor on one side (make sure to include units)
3. Put the known variable in the corresponding place of the ratio
4. Solve by "cross-multiplying"
I recognize that there are a lot of "math terms" in these steps, and understanding them can be daunting. I would include examples, but those are a bit difficult to type and even more difficult to understand. If this is all the information you need to solve the problems, then run with it. If you're thinking "what does this all mean" then face to face tutoring is the best way to show and explain these steps.