I would like to integrate a formula in my app that calculate the proportion of interest paid and capital paid in a paiement on X number of months. The problem is, I don’t know how to write a formuals that will repete itself X number of time… To be more precise I want to do something similar un Excel, where you can just slide your formuals down the page.

You can use the free Math.js plugin to add mathematical formulas to your page. Just add the Math.js element, which has no visibility, then plugin the numbers. Then you can call on that elements result to be displayed somewhere else. For instance if you had a repeating group and you added three text boxes. The first could display current cell’s DataType’s Payment, the second could display current cell’s DataType’s Capital, and the third could display Math.jsElement’s Result