The CAS Registry Mumber 1244-98-0 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,2,4 and 4 respectively; the second part has 2 digits, 9 and 8 respectively. Calculate Digit Verification of CAS Registry Number 1244-98: (6*1)+(5*2)+(4*4)+(3*4)+(2*9)+(1*8)=70 70 % 10 = 0 So 1244-98-0 is a valid CAS Registry Number.