1. **State the problem:** We need to find the sum of the following numbers: 22.8, 24.8, 23.5, 20.7, 20.8, 24.7, 25, 22.5, 21, 28.5, 22.6, 24.5, 20.9, 18.9, 16.1, 19.5, 17.8, 22.6, 24.4, 17.6, 21.9, 22.6, 25.1, 18.7, 24.2, 23.1, 18.4, 21.1, 18.6, 18.3, 19.3, 22.8, 18.1, 15.4, 23.6, 21.2, 17.8, 16.8, 20.3, 18.6. 2. **Formula used:** To find the sum of a list of numbers, we use the formula: $$\text{Sum} = x_1 + x_2 + x_3 + \cdots + x_n$$ where $x_i$ are the individual numbers. 3. **Add the numbers step-by-step:** $$22.8 + 24.8 = 47.6$$ $$47.6 + 23.5 = 71.1$$ $$71.1 + 20.7 = 91.8$$ $$91.8 + 20.8 = 112.6$$ $$112.6 + 24.7 = 137.3$$ $$137.3 + 25 = 162.3$$ $$162.3 + 22.5 = 184.8$$ $$184.8 + 21 = 205.8$$ $$205.8 + 28.5 = 234.3$$ $$234.3 + 22.6 = 256.9$$ $$256.9 + 24.5 = 281.4$$ $$281.4 + 20.9 = 302.3$$ $$302.3 + 18.9 = 321.2$$ $$321.2 + 16.1 = 337.3$$ $$337.3 + 19.5 = 356.8$$ $$356.8 + 17.8 = 374.6$$ $$374.6 + 22.6 = 397.2$$ $$397.2 + 24.4 = 421.6$$ $$421.6 + 17.6 = 439.2$$ $$439.2 + 21.9 = 461.1$$ $$461.1 + 22.6 = 483.7$$ $$483.7 + 25.1 = 508.8$$ $$508.8 + 18.7 = 527.5$$ $$527.5 + 24.2 = 551.7$$ $$551.7 + 23.1 = 574.8$$ $$574.8 + 18.4 = 593.2$$ $$593.2 + 21.1 = 614.3$$ $$614.3 + 18.6 = 632.9$$ $$632.9 + 18.3 = 651.2$$ $$651.2 + 19.3 = 670.5$$ $$670.5 + 22.8 = 693.3$$ $$693.3 + 18.1 = 711.4$$ $$711.4 + 15.4 = 726.8$$ $$726.8 + 23.6 = 750.4$$ $$750.4 + 21.2 = 771.6$$ $$771.6 + 17.8 = 789.4$$ $$789.4 + 16.8 = 806.2$$ $$806.2 + 20.3 = 826.5$$ $$826.5 + 18.6 = 845.1$$ 4. **Final answer:** The sum of all the numbers is **845.1**. This method ensures accuracy by adding each number sequentially and keeping track of the running total.