1. Calculate the following: a) (-215) mod 7 b) [77x (-65) + 147] mod 7 c) 442 mod 6 d) (55x26) mod 4 2. Find n div d and n mod d when: a) n = 10299, d =999 b) n =-2002, d =87 3. Some numbers and their prime factorizations are given below. 140 22.5.7 175 52.7 10782 7.11 25480 2. 5. 72. 13 . Use these prime factorizations to compute the following quantities. a) lcm(1078, 140) b) gcd(1078,140) c) ged(1078, 25480) d) lcm(175, 25480) 4. Use the Euclidean algorithm to find: a) ged(2406, 654) b) ged(630, 147)