Why might you want to use properties to change the order and grouping of the numbers in the following sum? - 45.2+(-7.9) +(-3.8)

-45.2 and - 7.9 are opposite numbers.

- 45.2 and -3.8 are opposite numbers.

-45.2 and -7.9 are compatible numbers.

-45.2 and -3.8 are compatible numbers.