The CAS Registry Mumber 53756-00-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,3,7,5 and 6 respectively; the second part has 2 digits, 0 and 0 respectively. Calculate Digit Verification of CAS Registry Number 53756-00: (7*5)+(6*3)+(5*7)+(4*5)+(3*6)+(2*0)+(1*0)=126 126 % 10 = 6 So 53756-00-6 is a valid CAS Registry Number.