How is adding decimals similar to adding whole numbers

If you know how to add and subtract whole numbers, then you can add and subtract decimals... to do this you put the numbers in a vertical column, aligning the decimal points. add each column of digits, starting on the right and working left. If the sum of a column is more than ten, "carry" digits to the next column on the left.

There both similar in a way seeing as you bring down the decimal and the answer an example would be

1
0.5
+ 0.8

1.3

I’m not sure how this works