5. Find the least common multiple (lcm) of the pairs of integers given in exercises 4. These were:

a). a=1,575 and b=231

b). a = -3719, b = 8416

c). a = 28,844, b = -15,712

6. Find the prime numbers less than or equal to the following natural numbers.

a) less than 200

b) less than 500

7. Find a (mod n) in each of the following cases.

a) a = 43,197, n = 39

b) a = -125,617, n = 315

8. Find a solution in each of the following congruencies

a) x = 7 (mod 9)

b) x = 4 (mod 12)

c) x = 16 (mod 21)

**Subject Computer Science Discrete Math**