1.  Change 1234₅  to base 10.

2.  Change 678₁₀ to base 5.

3.    2143₅ + 4311₅ = ___________₅                   4.  4311₅  -  2143₅ = ___________₅

5.  Make a times table for base 5         6.  Use your times table to find  2143₅ x 4₅
 

X	0	1	2	3	4
0
1
2
3
4

 

7.   13698 (mod 5) =

8.  In the real number system, if the product of two numbers is zero, then at least one of the numbers must be zero.  This is not true in clock arithmetic.  Give an example of two nonzero numbers whose product is 0 (mod n).  Specify n.  What property must n have so that the product of two numbers is never zero unless one of them is zero?