The CAS Registry Mumber 110579-78-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,0,5,7 and 9 respectively; the second part has 2 digits, 7 and 8 respectively. Calculate Digit Verification of CAS Registry Number 110579-78: (8*1)+(7*1)+(6*0)+(5*5)+(4*7)+(3*9)+(2*7)+(1*8)=117 117 % 10 = 7 So 110579-78-7 is a valid CAS Registry Number.