The CAS Registry Mumber 6244-47-9 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 6,2,4 and 4 respectively; the second part has 2 digits, 4 and 7 respectively. Calculate Digit Verification of CAS Registry Number 6244-47: (6*6)+(5*2)+(4*4)+(3*4)+(2*4)+(1*7)=89 89 % 10 = 9 So 6244-47-9 is a valid CAS Registry Number.