The CAS Registry Mumber 74059-78-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,4,0,5 and 9 respectively; the second part has 2 digits, 7 and 8 respectively. Calculate Digit Verification of CAS Registry Number 74059-78: (7*7)+(6*4)+(5*0)+(4*5)+(3*9)+(2*7)+(1*8)=142 142 % 10 = 2 So 74059-78-2 is a valid CAS Registry Number.