The CAS Registry Mumber 744-67-2 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 7,4 and 4 respectively; the second part has 2 digits, 6 and 7 respectively. Calculate Digit Verification of CAS Registry Number 744-67: (5*7)+(4*4)+(3*4)+(2*6)+(1*7)=82 82 % 10 = 2 So 744-67-2 is a valid CAS Registry Number.