1.  Does the set of real numbers, R, form a group under subtraction?  Justify.

2.  Consider the integers modulo 12, Z12, under multiplication.
a)  Determine whether [5] and [6] have multiplicative inverses in Z12.
Hint: It’s not necessary to construct a multiplication table as it’s quite big.
You can just form all the possible products of each numbers with the others.

b) Does Z12 form a group under multiplication?  Justify.

3.  Write 47.35123123123… as a ratio of two integers.

EPP (3rd Edition):
Section 4.1   #12, 28, 52

Section 4.2   #23

Section 6.1   #29, 35d

Section 6.2   #31

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