Question 01 (c)
Short answer questions: Each question carries 6 marks, your answers should quote the results being used and show your work.
Find the least positive residue of modulo 10
NOTE There was a typo in the original problem statement and the modulo 10 part was missing.
Make sure you understand the problem fully: What is the question asking you to do? Are there specific conditions or constraints that you should take note of? How will you know if your answer is correct from your work only? Can you rephrase the question in your own words in a way that makes sense to you?
If you are stuck, check the hint below. Consider it for a while. Does it give you a new idea on how to approach the problem? If so, try it!
Notice that and in fact this divides all values of for . This reduces the computation to a small finite set.
Checking a solution serves two purposes: helping you if, after having used the hint, you still are stuck on the problem; or if you have solved the problem and would like to check your work.
From the hint, we immediately see that