The CAS Registry Mumber 156914-70-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,5,6,9,1 and 4 respectively; the second part has 2 digits, 7 and 0 respectively. Calculate Digit Verification of CAS Registry Number 156914-70: (8*1)+(7*5)+(6*6)+(5*9)+(4*1)+(3*4)+(2*7)+(1*0)=154 154 % 10 = 4 So 156914-70-4 is a valid CAS Registry Number.