Question

how can you use a mental math and the inverse property of addition to find the sum [5.5 + (-2.3)] + (-5.5 + 2.3)?

Answer 1

Answer: it is 0

Explanation:

[5.5+(-2.3)] + (-5.5+2.3)

We can multiple (-5.5+2.3) by -1 so that it equals the first expression

[5.5+(-2.3)] + (-1)[5.5+(-2.3)]

Then, we change the + to -

[5.5+(-2.3)] - [5.5+(-2.3)]

since we are subtracting the same value, the answer is 0.

Answer 2

Hi you can do 5-3 is two then 5-2 is three so you get 3.2 then go to the either side and do 5-3 that equaled two and then do 5-2 that is three so you 3.2 then you add both of them together to get 6.4