Cant seem to calculate a simple formula

Sorry if this is an idiotc question but i am having trouble inputting a simple “programming style” calculation.
I am new to libre office and this help forum, so apologise if wrong place or…

=C3+((E3-C3)/2)
Is giving some strange numbers (see screenshot)

This above works fine in google docs.

But in Libre i am getting:

image description

Did you expect a value of 1231.5? The formula is correct. It’s just that in cell E3 you don’t have “Two thousand one hundred seventy-six” but only “two point one seven six”. Remove the comma, it spoils your calculations.

Be sure if your locale settings use comma or dot decimal separator. And use the proper one when you type-in your data. The LibreOffice can use both of them depended on the locale settings.