# How to write equations into the "make changes to data" action in workflow

Hi, I’m relatively new to bubble and am making a single-page native mobile flashcard app, which I want to utilise SM-2 (an algorithm for calculating intervals between flashcard reviews) for spaced repetition.
The way I’ve set it up is that there’s fields within my “flashcard” data type such as “ease”, “recall score”, “consecutive successful recalls”, and “interval”, which correspond to “EF”, “q”, “n”, and “I” (the values referenced in the algorithm below) respectively

However, when trying to create a workflow that updates the “ease”/“EF” , I am not allowed to enter an equation like the one in the above algorithm to calculate the new “ease” value, while also returning to enter "ease " in again to the equation.

I realise that I could simply create more fields within “flashcard” to represent the bracketed parts of the equation (such as creating a new field just for “5-recall score”, but I’m wondering if there’s an easier and more efficient way to enter equations such as this one.

Apologies for the wordy question

Any help is much appreciated!

Did you activate parenthesis in settings/versions

1 Like

I’ve done that (which I hadn’t done before so thank you!), but my problem doesn’t seem to be fixed. Ideally the workflow action would read
Ease = This Flashcard’s Ease + (0.1-(5- This Flashcard’s Recall score)*(0.08+(5- This Flashcard’s Recall score)*0.02))
however I can’t find a way to put this into that “change field” box

The main issue is the order of number. When you enter a number as first part (0.1 for example) it’s impossible to get the more to continue this expression. If you need to put a number first, instead, use arbitrary text:converted to number.
This Flashcard’s Ease + (arbitry text(0.1):converted to number- …