The document discusses writing expressions to represent earnings and perimeters. It provides examples of expressions for: 1) Hazel's earnings of 23d dollars for working 23 hours at a rate of d dollars per hour. 2) A worker's weekly salary of 40h dollars for working 40 hours at a rate of h = $5.15 per hour, which evaluates to $206. 3) The perimeter of Kylie's garden fence as the sum of side lengths 12 + 6a + 3a + 12 + 4a - 16, which simplifies to 13a + 18.