| §1.1 #1, 2, 5, 6, 7, 9, 10. Optional: 11. |
| Solutions: pdf, tex. |
| 1. Let a, b, q, r ∈ ℤ and b > 0. Define what we mean by ”when a is divided by b, the quotient is q and the remainder is r.&squo; |
| §1.1 #6: Let a, b, c ∈ ℤ. Suppose that when a is divided by b, the quotient is q and the remainder is r, and that when q is divided by c, the quotient is k and the remainder is s. Prove that when a is divided by bc, the quotient is k. |
| §1.2 #1abc, 4b, 9, 12, 13, 17, 22, 25. Optional: 33. |
| §1.3 #4, 18, 21. |
| Solutions: pdf, tex. |
| 1. State Bézout's lemma (Theorem 1.2). |
| §1.2 #25(a): If a, b, u, v ∈ ℤ are such that au + bv = 1, prove that (a,b) = 1. |
| (b): Show by example that if au + bv = d > 1, then (a,b) may not be d. |
| §1.3 #25, 35a. |
| §2.1 #1, 4, 6, 15, 20. |
| §14.1 #8, 9. Optional: 19, 20. |
| Solutions: pdf, tex. |
| 1. State Euclid's lemma (Theorem 1.5). |
| §2.1 #20(a): if a² ≡ b² (mod n) then a ≡ ± b (mod n). | /tr>
| (b): Same question when n is prime. |
| §3.1 #13, 27, 29, 31, 32. Optional: 44. |
| §3.2 #1, 3. |