Stationary-letterhead/business cards/compliment slip

After coming up with a logo I started on designing some stationary. Firstly the letterhead, I drew out some scamps to come up with different layout that I could possibly use. I wanted to keep a strong theme of mathematics and make this the main focus. The stock I am going to print these on is graph paper to emphasise the theme.

I chose a few of the designs and took them onto InDesign, I like the designs with the faded out logo best but also like the idea of incorporating shapes/diagrams subtly with a fainted opacity so that when printed onto graph paper they really have the look of a mathematical theme.

I pritned out the designs just on white paper to see how they look printed and looked for any errors/ changes that could be made

I then made some changes to the designs, some were incorrectly spelt, too small or needed the opacity to be smaller as they were too prominent. 

I just need to print onto graph paper now to see how they look on that.

I then took the same style onto designing a business card, this is just a first design and although has two pages it would actually only be printed on one and have the triangles from the logo embossed onto the front so it is a basic design with minimal text which displays the necessary information.

I need to come up with some further designs to develop this but I think it keeps the brand consistent.

I also deseigned a few compliment slips, again keeping the mathematical themein mind using the same elements but different arrangements.
Again, I need to devlop some more ideas to see what works best as a range.

I like the faded logo on the second design but I'm not sure if the layout works well with the address and details at the top, I think the first layout is more interesting but will have to work on some more ideas.