The CAS Registry Mumber 107610-38-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,7,6,1 and 0 respectively; the second part has 2 digits, 3 and 8 respectively. Calculate Digit Verification of CAS Registry Number 107610-38: (8*1)+(7*0)+(6*7)+(5*6)+(4*1)+(3*0)+(2*3)+(1*8)=98 98 % 10 = 8 So 107610-38-8 is a valid CAS Registry Number.