Recurring sum until single digit is obtained

Hi!

Just to get to my question directly: I’m trying to add two digits until I get a single digit number.
Does anyone have any suggestions?
Many thanks in advance!

E.g.
Step 1: 8+8=16.
Double digit answer, thereore, split the digits and sum again (step 2).
Step 2: 1+6=7.
Single digit, therefore calculation ends.

Here’s what I found in the forums so far:

  • “regext” seems to be mainly for text and it’s quite complicated. I’ve not managed to make it work, and hopefully there’s a simpler way.
    -“truncate” and “split” are all for text types, and there doesn’t seem to be a way to convert number type to text, then back to number for 2nd round of summation.
  • Having trouble with the “expressions” element. Looks like a possible/simple solution but can’t figure out how to make it work either. This related post doesn’t yet seem to have any clear tips on what to do: Extract digits from number and sum them - Need help / Database - Bubble Forum

Thanks again,
JW

you can use bubble beta expression composer to use pharenteses or math.js plugin to calculate it properly