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 (2^{2})(3) 
+ 
11 (2)(3^{2}) 
, the LCD is (2^{2})(3^{2}) = 36. 


Hence: 
13 12 
+ 
11 18 
= 
(13)(3) (12)(3) 
+ 
(11)(2) (18)(2) 
= 
(13)(3)+ (11)(2) 36 
= 
61 36 
