The CAS Registry Mumber 57699-78-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,7,6,9 and 9 respectively; the second part has 2 digits, 7 and 8 respectively. Calculate Digit Verification of CAS Registry Number 57699-78: (7*5)+(6*7)+(5*6)+(4*9)+(3*9)+(2*7)+(1*8)=192 192 % 10 = 2 So 57699-78-2 is a valid CAS Registry Number.