The CAS Registry Mumber 117068-31-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,7,0,6 and 8 respectively; the second part has 2 digits, 3 and 1 respectively. Calculate Digit Verification of CAS Registry Number 117068-31: (8*1)+(7*1)+(6*7)+(5*0)+(4*6)+(3*8)+(2*3)+(1*1)=112 112 % 10 = 2 So 117068-31-2 is a valid CAS Registry Number.