When adding decimals by hand, the correct approach involves a few straightforward, yet crucial steps to ensure accuracy. Here is a step-by-step detailed solution:
1. Line up the Decimal Points: When adding decimal numbers, the most important step is to align the numbers by their decimal points. This ensures that each digit is in the correct decimal place (units, tenths, hundredths, etc.).
2. Add from Right-to-Left: Once the numbers are aligned by their decimal points, you should begin adding from the rightmost digit (the smallest decimal place value, which might be the hundredths, thousandths, etc.), and move towards the left. This is because if there is any carryover, it can be easily added to the next column to the left.
Given these steps, the correct answer among the options provided is:
Line up the decimals of the numbers then add from right-to-left
