Part III
Notes for chapters 3, 4, and 5

20 Notes for the sixth week: digits, bases, and operations
 20.1 Positional Numbers
 20.2 Converting Between Bases
 20.3 Operating on Numbers
 20.4 Homework
21 Solutions for sixth week’s assignments
 21.1 Problem set 3.1
 21.2 Problem set 3.2
 21.3 Problem set 3.3
 21.4 Problem set 3.4
22 Notes for the seventh week: primes, factorization, and modular arithmetic
 22.1 Divisibility
 22.2 Primes
 22.3 Factorization
 22.4 Modular Arithmetic
 22.5 Divisibility Rules
 22.6 Homework
23 Solutions for seventh week’s assignments
 23.1 Problem set 4.1
 23.2 Two diagrams
 23.3 Problem set 4.2
 23.4 A familiar incomplete integer
24 Notes for the eighth week: GCD, LCM, and ax + by = c
 24.1 Modular arithmetic
 24.2 Divisibility rules
 24.3 Greatest common divisor
 24.4 Least common multiple
 24.5 Euclidean GCD algorithm
 24.6 Linear Diophantine equations
 24.7 Homework
25 Solutions for eighth week’s assignments
 25.1 Problem set 4.3
 25.2 Computing GCDs
 25.3 Computing LCMs
 25.4 Linear Diophantine equations
26 Notes for the ninth week: ax + by = c, fractions
 26.1 Linear Diophantine equations
 26.2 Into real numbers
 26.3 Rational numbers
 26.4 Review of rational arithmetic
 26.5 Complex fractions
 26.6 Homework
27 Solutions for ninth week’s assignments
 27.1 Diophantine equations
 27.2 Problem set 6.1
 27.3 Problem set 6.2
 27.4 Problem set 6.3
28 Notes for the tenth week: Irrationals and decimals
 28.1 Real numbers
 28.2 Exponents and roots
 28.3 Decimal expansions and percentages
 28.4 Fixed and floating-point arithmetic
 28.5 Homework
29 Second exam and solutions
30 Third exam, due 1 December
31 Third exam solutions
32 Final exam