1. The problem is to find the sum of the numbers: 2,400,000, 2,100,000, 2,100,000, 1,500,000, 1,200,000, and 900,000. 2. The formula for the sum of a list of numbers $a_1, a_2, \ldots, a_n$ is: $$\text{Sum} = a_1 + a_2 + \cdots + a_n$$ 3. Add the numbers step-by-step: $$2,400,000 + 2,100,000 = 4,500,000$$ 4. Add the next number: $$4,500,000 + 2,100,000 = 6,600,000$$ 5. Continue adding: $$6,600,000 + 1,500,000 = 8,100,000$$ 6. Add the next number: $$8,100,000 + 1,200,000 = 9,300,000$$ 7. Finally, add the last number: $$9,300,000 + 900,000 = 10,200,000$$ 8. Therefore, the sum of the numbers is: $$\boxed{10,200,000}$$