MATH 140 Test 2 Spring 1999 Name________________________

1. Find the prime factorizations of each of the following: (12)

a) 5100 = ________

b) 627 = _________

c) 899 = _________

2. Determine if 161 is a prime and briefly explain your method. (8)

3. Find d(8700). d(8700) = _________ (6)

4. Find GCD(756,889) using the Euclidean Algorithm. ____________ (6)

5. Find LCM(51,119) by any method. ____________ (6)

6. Use the divisibility tests to determine if 1266 is divisible by 6. Explain (6)

briefly your tests.

7.) Perform each of the following operations in the given base . (20)

a) 2413₅ b) 20100₁₂ c) 332₅

3442₅ -1123₁₂ x 432₅

+1442₅

d)

8. Explain why is undefined. (4)

9) Does division have an identity element? If not give an example to illustrate your answer. (4)

10) Test the number 13398 for divisibility by the numbers from 2 to 11. (10)

11. Which of the following are true? In those cases justify your answer. (6)

a)

b)

c)

12. 120 is divided by the whole number b. The quotient is 17 and the remainder

is 1. Find the number b. (4)

13. Is 24 + 8 ¸ 2 = 15? If not, why not? (4)

14. Perform the following using scratch addition: (4)

678

352

986

376

+878