Google Sheets - IF with ISBLANK

I am working in google sheets and I would like to ask you one thing. I want to check if cell is blank and if it is it should return 0, if it is not it should calculate the formula, which I have used befere. https://i.stack.imgur.com/Qh4dc.png (can not post image...) But I am still getting this #ERROR! which says error when analyzing formula. I have tried it in Microsoft Excel and exact formula works...

Did somebody already solved this? Thanks a lot! 👌