The CAS Registry Mumber 61134-57-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,1,1,3 and 4 respectively; the second part has 2 digits, 5 and 7 respectively. Calculate Digit Verification of CAS Registry Number 61134-57: (7*6)+(6*1)+(5*1)+(4*3)+(3*4)+(2*5)+(1*7)=94 94 % 10 = 4 So 61134-57-4 is a valid CAS Registry Number.