# Homework Hints 2-2

[tippy title=”Problems 1-2″]Problems 1-2
There are many problems throughout the text labeled IN YOUR OWN WORDS.

Make sure you understand the operations of union, intersection, and complement
(Problem 1).

Problem 2 is interesting because it is taken from the California Assessment Program. It is based on the formula for the cardinality of the union of two sets. Relax; do not be afraid answer using your own words.[/tippy]

[tippy title=”Problem 3″]Problem 3
Remember intersection is “and”, union is “or,” and complement is “not.”[/tippy]

[tippy title=”Problems 1-4″]Problem 4
You should remember both of these formulas.[/tippy]

[tippy title=”Problems 5″]Problem 5
Remember the conditions under which this is true.[/tippy]

[tippy title=”Problem 6″]Problem 6 Try to find a counter-example.[/tippy]

[tippy title=”Problems 7 and 8; 9 and 10″]Problems 7 and 8; 9 and 10
Contrast union, intersection, and complement for the given sets.[/tippy]

[tippy title=”Problems 11-12″]Problems 11-12
These are complements; to find the complement of a set, look at the universe
(set U), and list all elements in the universe that are not in the given set. Notice that Problems 11 and 17 are the same, and so are Problems 12 and 18.[/tippy]

[tippy title=”Problems 13-16″]Problems 13-16
For multiples of three, “count by 3”; {3, 6, 9, … }
For multiples of five, “count by 5”; {5, 10, 15, … }[/tippy]

[tippy title=”Problems 17-18″]Problems 17-18
These are complements; to find the complement of a set, look at the universe
(set U), and list all elements in the universe that are not in the given set. Notice that Problems 11 and 17 are the same, and so are Problems 12 and 18.[/tippy]

[tippy title=”Problems 19-24″]Problems 19-24
These problems deal with unions, intersections, and complements.[/tippy]

[tippy title=”Problems 19, 21a, 23b, and 24a”]Problems 19, 21a, 23b, and 24a
These are unions; to find the union of two sets first list all of the elements in the given sets using rosters, and then select those elements that are in either of the given sets. Remember, the empty set is { }.[/tippy]

[tippy title=”Problems 20, 23a, and 23b”]Problems 20, 23a, and 24b
These are intersections; to find the intersection of two sets first list all of the elements in the given sets using rosters, and then select those elements that are in both of the given sets. Remember, the empty set is { }.[/tippy]

[tippy title=”Problem 22″]Problems 22
These are complements; the universe and empty sets are complements.[/tippy]

[tippy title=”Problems 25, 27, 30, 37, and 39″]Problems 25, 27, 30, 37, and 39
These are unions; to find the union of two sets first list all of the elements in the given sets using rosters, and then select those elements that are in either of the given sets.[/tippy]

[tippy title=”Problems 26, 28, 29, 38, and 40″]Problems 26, 28, 29, 38 and 40
These are intersections; to find the intersection of two sets first list all of the elements in the given sets using rosters, and then select those elements that are in both of the given sets.[/tippy]

[tippy title=”Problems 31-35″]Problems 31-35
These are complements; remember, complement is relative to the universe.[/tippy]

[tippy title=”Problems 41-46″]Problems 41-46
See Figure 2.7.[/tippy]

[tippy title=”Problems 47-52″]Problems 47-52
See Example 1 for union and intersection; and Figure 2.2 for complement.[/tippy]

[tippy title=”Problems 53-58″]Problems 53-58
See Example 3. Draw two interlocking circles within a rectangle representing the universe. Next, label the circles and fill in the number in the intersection first. Finally, fill in the number in the remaining regions by using subtraction. [/tippy]

### Note: Homework Hints are given only for the Level 1 and Level 2 problems.

However, as you go through the book be sure you look at all the examples in the text. If you need hints for the Level 3 problems, check some sources for help on the internet (see the LINKS for that particular section). As a last resort, you can call the author at (707) 829-0606.

On the other hand, the problems designated “Problem Solving” generally require techniques that do not have textbook examples.

There are many sources for homework help on the internet.

Algebra.help
Here is a site where technology meets mathematics. You can search a particular topic or choose lessons, calculators, worksheets for extra practice or other resources.
http://www.algebrahelp.com/