The CAS Registry Mumber 76893-42-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,6,8,9 and 3 respectively; the second part has 2 digits, 4 and 2 respectively. Calculate Digit Verification of CAS Registry Number 76893-42: (7*7)+(6*6)+(5*8)+(4*9)+(3*3)+(2*4)+(1*2)=180 180 % 10 = 0 So 76893-42-0 is a valid CAS Registry Number.