One way is by comparing the weather for today as compared to the rest of the week or month.
To start, the first thing you need to know is that when you add decimals, you must line the decimal up, meaning, if you were adding 2.7+4.1, you have to make sure 2 is lined up with 4, and 7 is lined up with 1 so that the decimals align. Then, you add straight down from right to left and you get 6.8 as your answer.
The answer to the question is 48cm^2