Here are the results of the additions:

1. $68040 + 2520 = 70560$
2. $20.79 + 2.31 = 23.10$
3. $145.89 + 16.21 = 162.10$
4. $11145.25 + 796.10 = 11941.35$
5. $5397.70 + 385.55 = 5783.25$
6. $4815.44 + 343.96 = 5159.40$
7. $41.0984 + 5.1373 = 46.2357$

Would you like a more detailed breakdown of any of these calculations?

Here are 5 related questions to further explore the topic:

1. What is the sum of 12345.67 and 8901.23?
2. How do you perform addition with numbers that have different decimal places?
3. What happens when you add very large numbers to very small numbers?
4. Can you explain the importance of lining up decimal points when adding?
5. How would you verify the accuracy of a long addition?

Tip: When adding numbers with decimals, always align the decimal points to ensure accuracy.