The CIE Computer Science Syllabus covers binary, hexa and denary number systems in the syllabus. We are working on collecting notes on O Level Computer Science 2210 course as the book as not been published yet. Our motto is “not to reinvent the wheel”. So I came across a very good resource for Number Systems:
http://www.ruknuddin.com/workbook_number_system.pdf
It even out lines the syllabus section that covers the Number Systems.