The CAS Registry Mumber 53878-05-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,3,8,7 and 8 respectively; the second part has 2 digits, 0 and 5 respectively. Calculate Digit Verification of CAS Registry Number 53878-05: (7*5)+(6*3)+(5*8)+(4*7)+(3*8)+(2*0)+(1*5)=150 150 % 10 = 0 So 53878-05-0 is a valid CAS Registry Number.