The CAS Registry Mumber 1257649-57-2 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,2,5,7,6,4 and 9 respectively; the second part has 2 digits, 5 and 7 respectively. Calculate Digit Verification of CAS Registry Number 1257649-57: (9*1)+(8*2)+(7*5)+(6*7)+(5*6)+(4*4)+(3*9)+(2*5)+(1*7)=192 192 % 10 = 2 So 1257649-57-2 is a valid CAS Registry Number.