The CAS Registry Mumber 85263-70-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,5,2,6 and 3 respectively; the second part has 2 digits, 7 and 0 respectively. Calculate Digit Verification of CAS Registry Number 85263-70: (7*8)+(6*5)+(5*2)+(4*6)+(3*3)+(2*7)+(1*0)=143 143 % 10 = 3 So 85263-70-3 is a valid CAS Registry Number.