Adding and Subtracting decimals

In Te Ngahere we have been learning how to add and subtract decimals. I found out that
the easiest strategy to add and subtract decimals was to round the number to a tidy
number. For example, 2 . 8 + 1 . 5 you would have to add 0 . 2 on to 2 . 8 to get 3 so you would do the same on the 1 . 5 but instead you would subtract 0 . 2 - 1 . 5 which equals 1 . 3 so you would have to add 3 + 1 . 3 = 3 . 3. I found this strategy better than others. Because some of the other strategies confuse me and I don’t really understand them. My next goal for decimals would be to learn different strategies.