The CAS Registry Mumber 22286-71-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,2,2,8 and 6 respectively; the second part has 2 digits, 7 and 1 respectively. Calculate Digit Verification of CAS Registry Number 22286-71: (7*2)+(6*2)+(5*2)+(4*8)+(3*6)+(2*7)+(1*1)=101 101 % 10 = 1 So 22286-71-1 is a valid CAS Registry Number.