MY APPROACH TO TEACHING and to the offered UNITS on this website is to pepper the worksheets (and, optionally, the quizzes) with informational guides that serve as text-book-like how-to instructions. How the teacher puts it all together is left to that teacher's unique approach to teaching. In other words, these offerings are PROBLEM-BASED and not lesson-plan based. The difference is profound. I do not pretend to know how you should speak to your students and refuse to offer canned lesson plans--the material will serve as your own guide as well as for the students themselves.
Number bases are critical to a student's understanding of number theory but the topic is oddly left out of the Common Core. A full unit is included here since I have close to 2,000 problems in various areas that are NOT within the Common Core outline.
The reason for the 4 different length worksheets is that each teacher has different time constraints that might pertain to this unit.
[The problems in All WORKSHEETS and PREVIEWS are printed in difficulty (1 [easy], 2 [not so easy], 3 [proficiency] up to 4 [mastery]) order within a skill. The actual difficulty level appears slightly to the left of the DK box of each problem in a very small font. Also, instructional references appear on worksheets but are optional on quizzes.]
As of 2/9/15 I have made the following revisions to this product:
1. the addition of a moderate difficulty assessment (level 2) with answer key
2. the addition of a more difficult assessment (level 3) with answer key
THE IDEA BEHIND THE ASSESSMENTS IS THAT ONE OR BOTH MAY BE USED IN CONJUNCTION WITH THE WORKSHEETS.
You might also want to check out the Grade 8 Summary
which has links to many related offerings here.
In addition, the following is another unit that might interest you: the UNIT on the Pythagorean Theorem