The CAS Registry Mumber 107694-26-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,7,6,9 and 4 respectively; the second part has 2 digits, 2 and 6 respectively. Calculate Digit Verification of CAS Registry Number 107694-26: (8*1)+(7*0)+(6*7)+(5*6)+(4*9)+(3*4)+(2*2)+(1*6)=138 138 % 10 = 8 So 107694-26-8 is a valid CAS Registry Number.