The CAS Registry Mumber 55749-15-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,5,7,4 and 9 respectively; the second part has 2 digits, 1 and 5 respectively. Calculate Digit Verification of CAS Registry Number 55749-15: (7*5)+(6*5)+(5*7)+(4*4)+(3*9)+(2*1)+(1*5)=150 150 % 10 = 0 So 55749-15-0 is a valid CAS Registry Number.