Answer:
To use mental math and the inverse property of addition to find the sum [5.5+(-2.3)] +(-5.5 + 2.3), you can use the following steps:
Rewrite the expression as [5.5+(-2.3)] +(-5.5) + 2.3.
Use the inverse property of addition to rewrite (-5.5) as 5.5, so the expression becomes [5.5+(-2.3)] +(5.5) + 2.3.
Use the inverse property of addition again to rewrite (-2.3) as 2.3, so the expression becomes [5.5+2.3] +(5.5) + 2.3.
Use the associative property of addition to rearrange the terms in the expression, so it becomes 5.5 + 2.3 + 5.5 + 2.3.
Use mental math to add the terms, which gives you a result of 15.8.
Therefore, the sum of [5.5+(-2.3)] +(-5.5 + 2.3) is 15.8.
Explanation: