The odd-even ratio of the rightmost digit of sum of any two numbers

The ratio of odd and even numbers in the rightmost digit of sum of any two numbers in the .

Odd Numbers: such as 1,3,5,7,9...

Even Numbers: such as 0,2,4,6,8...

0: 0 odd number(s)，4 even number(s)

1: 1 odd number(s)，3 even number(s)

2: 2 odd number(s)，2 even number(s)

3: 3 odd number(s)，1 even number(s)

4: 4 odd number(s)，0 even number(s)

5: 5 odd number(s)，-1 even number(s)

6: 6 odd number(s)，-2 even number(s)