Question 1
Which statement best describes a binary operation on a set $S$?
Question 2
Which of the following is NOT a binary operation on the set of integers $\mathbb{Z}$?
Question 3
What does closure mean for a binary operation on a set $S$?
Question 4
Is the rule $a*b=\sqrt{a-b}$ a binary operation on $\mathbb{R}$?
Question 5
What is the identity element for addition on the integers $\mathbb{Z}$?
