If it is not necessarily the same, 1 1 has the answer:
50-(0)=40+( 10)
50-( 1)=40+(9)
50-(2)=40+(8)
50-(3)=40+(7)
50-(4)=40+(6)
50-(5)=40+(5)
50-(6)=40+(4)
50-(7)=40+(3)
50-(8)=40+(2)
50-(9)=40+( 1)
50-( 10)=40+(0)