The CAS Registry Mumber 1276042-77-3 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,2,7,6,0,4 and 2 respectively; the second part has 2 digits, 7 and 7 respectively. Calculate Digit Verification of CAS Registry Number 1276042-77: (9*1)+(8*2)+(7*7)+(6*6)+(5*0)+(4*4)+(3*2)+(2*7)+(1*7)=153 153 % 10 = 3 So 1276042-77-3 is a valid CAS Registry Number.