|
Suggestions for this self exam: |
|
[A] |
Study text section 4.3 , but then keep your book closed during this
entire test |
|
[B] |
Enter your answers in the boxes provided. Check them when you've finished. |
|
[C] |
|
Remember the general rules: |
a
b |
= |
ac
bc |
and also |
a
d |
+ |
b
d |
= |
a + b
d |
|
|
[D] |
The LCD ("least common denominator": "d" in the paragraph above),
is the smallest number which is a multiple of all denominators in a sum.
Typically, we find the LCD
by factoring all denominators into prime (unfactorable) expressions.
The LCD then includes any prime expression as a factor, and
includes it as many times as that denominator which contains
it most abundantly. |
| |
|
Thus, for |
13
12 |
+ |
11
18 |
= |
13
(22)(3) |
+ |
11
(2)(32) |
, the LCD is (22)(32) = 36. |
|
| |
| Hence: |
13
12 |
+ |
11
18 |
= |
(13)(3)
(12)(3) |
+ |
(11)(2)
(18)(2) |
= |
(13)(3)+ (11)(2)
36 |
= |
61
36 |
|
