The CAS Registry Mumber 1065506-69-5 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,0,6,5,5,0 and 6 respectively; the second part has 2 digits, 6 and 9 respectively. Calculate Digit Verification of CAS Registry Number 1065506-69: (9*1)+(8*0)+(7*6)+(6*5)+(5*5)+(4*0)+(3*6)+(2*6)+(1*9)=145 145 % 10 = 5 So 1065506-69-5 is a valid CAS Registry Number.