Answer :

Their sum is - 2.09.

How to find the sum?

Given,

5.31+(-7.40)

Solution:

5.31+(-7.40) = 5.31 - 7.40 (Since sum of + and - is -)

                   = - 2.09

Their sum is - 2.09.

To learn more about the sum, refer

brainly.com/question/17695139

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