You can calculate, for example, if it's worth buying a promotional product like that:
"Buy 70gr of biscuit for € 4.98 or 140gr for € 9.97".
Would not it be more advantageous to buy 2 of 70gr instead of 1 per 140gr?
Well, you can draw your own conclusions using the application for a multitude of calculations.
The App also a great tool for children to get a notion of how can I calculate proportions using the rule of three and thus, begin to use day-to-day.
Available in English, Portuguese and Spanish.