Proportions and Conversions made easy using Cross multiplication

This is the most simple and clearest method to lay out questions of Percentage Growth and Reduction, Proportions, Volume to Weight, to find unknown quantity. It can also help with many other Maths problems - Speed/Distance/Time , Currency conversions, Pharmacy calculations simplified using this method.
If you have difficulty remembering 'what to put where' when it comes to these maths questions then try this method of just keeping ‘like with like’
How to write these math questions down as 'Ratio-based' Equations