The CAS Registry Mumber 35106-78-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,5,1,0 and 6 respectively; the second part has 2 digits, 7 and 8 respectively. Calculate Digit Verification of CAS Registry Number 35106-78: (7*3)+(6*5)+(5*1)+(4*0)+(3*6)+(2*7)+(1*8)=96 96 % 10 = 6 So 35106-78-6 is a valid CAS Registry Number.