Are the problems too close together? Make sure you can distinguish between the problem number and the actual problems. The problem numbers should be less obtrusive. Students with and without ADD and ADHD can become distracted by too many distractions!?
Developers of free math worksheets primarily use either of two methods for displaying and printing worksheets on the Internet. PDF pages require an additional piece of software, Adobe Acrobat, which should automatically open worksheets in your browser. PDF worksheets theoretically cannot be manipulated and display/print precisely as the developer designed. The second mode of delivery, HTML code, displays worksheets directly in your browser window. The downside of using HTML based worksheets is they are prone to printing problems. A worksheet meant for one page can easily bleed over to a second sheet.