This math topic focuses on calculating total costs and earnings using unit rates. It centers on two primary scenarios: determining total cost from given total weights and per unit prices, and calculating total earnings from total hours worked and hourly wages. Aside of basic arithmetic, this topic emphasizes real-world application of ratios and unit rates in financial contexts, enhancing problem-solving skills in a practical setting. Each problem provides multiple choice answers, reinforcing the concept of unit rate calculations in everyday scenarios.