Formulas and calculation

Hi!

I need you to permit use of formulas in the mind map like this image under:

For example, as I insert the values 2, 3 and 5 in the childs, the main line would, automatically, calculate, from a formula, the sum and show the result (as the image above).

Would this feature be possible? (please say yes...) That would be very important to me.

Thanks!