Question

The sum of three numbers is 19 13/30. Two of the numbers are 5 2/3 and 6 1/6, What is the third number?

Answer 1

let the third number is x
x + 5 2/3 + 6 1/6 = 19 13/30
solve for x

Answer 2

Another way to go but a bit more complex...turn this into a decimal
x + 5.67 + 6.16 = 19.43 (div 13/30 to get decimal)
x = 19.43-5.67-6.16 = 7.6
or x = 7 3/5