The CAS Registry Mumber 496780-24-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 4,9,6,7,8 and 0 respectively; the second part has 2 digits, 2 and 4 respectively. Calculate Digit Verification of CAS Registry Number 496780-24: (8*4)+(7*9)+(6*6)+(5*7)+(4*8)+(3*0)+(2*2)+(1*4)=206 206 % 10 = 6 So 496780-24-6 is a valid CAS Registry Number.