Write out each expression with numbers first.
3). (1 point each) Evaluate these expressions for: d = +8 e = +4 f = - 2:
 a). d/e = _______ . b). de = _______ . c). f + d = _______ . d). f + d - e = _______ . e). 4e + 3d = _______ . f). 8d - 9e = _______ . g). f + e = _______ . h). 8de = _______ . i). 5ed = _______ . j). e/d = _______ . k). f + 2e = _______ . l). d9/e = _______ .

4). (1 point each) Evaluate these expressions for: a = 1/2 b = 1/4 c = 1/3
 a). a + b = ______. b). ab = ______. c). a - b = ______. d). abc = ______. e). ac = ______ f). 2a = ______
5). (3 points)[Extra credit]
Beth has saved 3 1/2 books of trading stamps. How many more books of stamps does Beth need to get a backpack and frame that cost 6 3/4 books?

6). (3 points)[Extra credit]
A prime number is a number that can only be divided evenly by itself and 1. Here are the prime numbers from 1 to 100:
2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,91,97.
find 2 two-digit prime numbers whose digits sum to 7.