I am having a hard time understanding the formulas (Im new to this and trying to build basic formulas to learn). 

In my products, I have created a custom decimal field called "labor hours"I want to create a forumla field next to it that will times that number by 100 (my hourly rate) to give me the total hourly cost of a product. 

so I would want to create something like 

Products.Hourly Rate * 100 = $

so if I add 2. 5 in the amount of hours the product takes me to complete, the forumla field should show $250. does this make sense? 

I have tried several things and always get a syntax error when I check it. I woudl imagine this is a pretty simple forula.