The CAS Registry Mumber 4722-47-8 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,7,2 and 2 respectively; the second part has 2 digits, 4 and 7 respectively. Calculate Digit Verification of CAS Registry Number 4722-47: (6*4)+(5*7)+(4*2)+(3*2)+(2*4)+(1*7)=88 88 % 10 = 8 So 4722-47-8 is a valid CAS Registry Number.