The CAS Registry Mumber 89744-49-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,9,7,4 and 4 respectively; the second part has 2 digits, 4 and 9 respectively. Calculate Digit Verification of CAS Registry Number 89744-49: (7*8)+(6*9)+(5*7)+(4*4)+(3*4)+(2*4)+(1*9)=190 190 % 10 = 0 So 89744-49-0 is a valid CAS Registry Number.