The CAS Registry Mumber 790299-78-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 7,9,0,2,9 and 9 respectively; the second part has 2 digits, 7 and 8 respectively. Calculate Digit Verification of CAS Registry Number 790299-78: (8*7)+(7*9)+(6*0)+(5*2)+(4*9)+(3*9)+(2*7)+(1*8)=214 214 % 10 = 4 So 790299-78-4 is a valid CAS Registry Number.