The CAS Registry Mumber 1173097-22-7 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,1,7,3,0,9 and 7 respectively; the second part has 2 digits, 2 and 2 respectively. Calculate Digit Verification of CAS Registry Number 1173097-22: (9*1)+(8*1)+(7*7)+(6*3)+(5*0)+(4*9)+(3*7)+(2*2)+(1*2)=147 147 % 10 = 7 So 1173097-22-7 is a valid CAS Registry Number.