The CAS Registry Mumber 107586-78-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,7,5,8 and 6 respectively; the second part has 2 digits, 7 and 8 respectively. Calculate Digit Verification of CAS Registry Number 107586-78: (8*1)+(7*0)+(6*7)+(5*5)+(4*8)+(3*6)+(2*7)+(1*8)=147 147 % 10 = 7 So 107586-78-7 is a valid CAS Registry Number.