What plus what equals -36?

Answer 1

There are infinitely many answers.

Start with integers:

-39, 3

-38, 2

-37, 1

-36, 0

-35, -1

-34, -2

the list can be extended in both directions.

Now, between and two integers, there are infinitely many rational numbers, ad each one has a partner such that their sum will be -36. For example,

-37.2, 1.2

-37.1, 1.1 [37.0 has already been done, as 37]

-36.9, 0.9

-36.8, 0.8

...

-36.1, 0.1 [36.0 has already been done, as 36]

-35.9, -0.1

etc.

And then there are decimals to 2 digits, to 3 digits, ...

And then you can bring in Irrational Numbers

Finally, if you are really adventurous, you could use pairs of complex numbers as well.