The CAS Registry Mumber 868784-12-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 8,6,8,7,8 and 4 respectively; the second part has 2 digits, 1 and 2 respectively. Calculate Digit Verification of CAS Registry Number 868784-12: (8*8)+(7*6)+(6*8)+(5*7)+(4*8)+(3*4)+(2*1)+(1*2)=237 237 % 10 = 7 So 868784-12-7 is a valid CAS Registry Number.