The CAS Registry Mumber 214678-27-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 2,1,4,6,7 and 8 respectively; the second part has 2 digits, 2 and 7 respectively. Calculate Digit Verification of CAS Registry Number 214678-27: (8*2)+(7*1)+(6*4)+(5*6)+(4*7)+(3*8)+(2*2)+(1*7)=140 140 % 10 = 0 So 214678-27-0 is a valid CAS Registry Number.