Solutions
Ch 19, Euler's Phi Function and Sums of Divisors Ch 20, Powers Modulo p and Primitive Roots
First Edition: 18.1, 18.3(a), 19.1, 19.2 Second Edition: 18.1, 18.4(a), 19.1, 19.2
First Edition: 18.3(b) Second Edition: 18.4(b)