The CAS Registry Mumber 75794-13-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,5,7,9 and 4 respectively; the second part has 2 digits, 1 and 3 respectively. Calculate Digit Verification of CAS Registry Number 75794-13: (7*7)+(6*5)+(5*7)+(4*9)+(3*4)+(2*1)+(1*3)=167 167 % 10 = 7 So 75794-13-7 is a valid CAS Registry Number.