The CAS Registry Mumber 79108-52-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,1,0 and 8 respectively; the second part has 2 digits, 5 and 2 respectively. Calculate Digit Verification of CAS Registry Number 79108-52: (7*7)+(6*9)+(5*1)+(4*0)+(3*8)+(2*5)+(1*2)=144 144 % 10 = 4 So 79108-52-4 is a valid CAS Registry Number.