How many pairs of while number have a sum of 110

There is a lot of numbers

56

The way you figure this out is to first recall that Whole Numbers = 0, 1, 2, 3, 4, ...

Then, just start pairing numbers up:

0, 110
1, 109
2, 108
3, 107

and so forth.

What you realize is that you have a bunch of pairs of numbers that start with (0, 110) and end with (55, 55)

Once you get beyond 55, the pairs start repeating themselves:

(54, 56) is the same as (56, 54)

So, if you start with zero and go up to 55, you would have a total of 56 unique pairs of numbers that would sum to 110.

Hope this helps!

Good luck

The amount used= 13.04- 1.9 = 11.14