The CAS Registry Mumber 78949-24-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,8,9,4 and 9 respectively; the second part has 2 digits, 2 and 4 respectively. Calculate Digit Verification of CAS Registry Number 78949-24: (7*7)+(6*8)+(5*9)+(4*4)+(3*9)+(2*2)+(1*4)=193 193 % 10 = 3 So 78949-24-3 is a valid CAS Registry Number.