The CAS Registry Mumber 167774-59-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,6,7,7,7 and 4 respectively; the second part has 2 digits, 5 and 9 respectively. Calculate Digit Verification of CAS Registry Number 167774-59: (8*1)+(7*6)+(6*7)+(5*7)+(4*7)+(3*4)+(2*5)+(1*9)=186 186 % 10 = 6 So 167774-59-6 is a valid CAS Registry Number.