Hey there:
Have a look here:
https://help.encharge.io/article/123-personalizing-emails-with-liquid
and here https://shopify.github.io/liquid/

This is a very important feature, this way we can set a LifTime Value field thats is so important for paid ads this days. Prokopis can you help me with one question while this is available? If i have a $27.00 sale, should i set the number field with 27.00 or 2700 in order to apply the action you share in your comment? Thanks for your help.

You can already do this by using liquid programming but an easier way would be great. Here's an example for adding 50% reward credit for every purchase:

Trigger: Webhook of a sale that records the transaction price in cents

Action: Set field "Rewards" to
{{person.NewPurchase | divided_by: 200 | plus: person.Rewards | round}}

This divides the amount by 200 to get the 50% of the sale price. the "plus:" adds it to the amount that is already there and the "round" rounds up the decimals.

+1! Would be great if we can perform math calculations as actions.

 For example, If I want to add +1 to a custom field (number pages visited) each time a subscriber visit one of my pages, to know how many times visited my site. Of course can be done with lead scoring, but I would like to use this feature only for warm leads and for selling proposition.