The CAS Registry Mumber 112712-57-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,2,7,1 and 2 respectively; the second part has 2 digits, 5 and 7 respectively. Calculate Digit Verification of CAS Registry Number 112712-57: (8*1)+(7*1)+(6*2)+(5*7)+(4*1)+(3*2)+(2*5)+(1*7)=89 89 % 10 = 9 So 112712-57-9 is a valid CAS Registry Number.