The CAS Registry Mumber 1948-05-6 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,9,4 and 8 respectively; the second part has 2 digits, 0 and 5 respectively. Calculate Digit Verification of CAS Registry Number 1948-05: (6*1)+(5*9)+(4*4)+(3*8)+(2*0)+(1*5)=96 96 % 10 = 6 So 1948-05-6 is a valid CAS Registry Number.