Need help working out my average mark on a module...

Not a maths student but no idea where else to turn so hopefully someone can help me out. In the module guidlines it states:
"To pass any module, students must obtain a mark of 40% or higher on average (taking all components of assessment together). Where there is more than one component of assessment you do not have to pass each component, as long as you get an average of 40% or above, and as long as you don’t get less than 20% for any single component."

How the heck do I work out my average mark? I tried using an online calculator which just kept telling me that my average mark was 0%, so if anyone else can help, I would be really grateful.

Assignment 1: Mark-41. Weighting-20%
Assignment 2: Mark 52. Weighting-30%
Assignment 3: Mark-65. Weighting-15%
Assignment 4: Mark-25. Weighting-35%

In terms of percentage of the whole grade, I think this gives me
Assignment 1: 8.2%
Assignment 2: 15.3%
Assignment 3: 9.75%
Assignment 4: 8.75%

Adding these up gives me a total of 42%-but is this mark my average grade? Really kinda confused on this, so thanks to anyone who can help reassure me...

Are all of the marks out of 100?

Yes they are.