The CAS Registry Mumber 157825-93-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,5,7,8,2 and 5 respectively; the second part has 2 digits, 9 and 3 respectively. Calculate Digit Verification of CAS Registry Number 157825-93: (8*1)+(7*5)+(6*7)+(5*8)+(4*2)+(3*5)+(2*9)+(1*3)=169 169 % 10 = 9 So 157825-93-9 is a valid CAS Registry Number.