The CAS Registry Mumber 105776-59-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,5,7,7 and 6 respectively; the second part has 2 digits, 5 and 9 respectively. Calculate Digit Verification of CAS Registry Number 105776-59: (8*1)+(7*0)+(6*5)+(5*7)+(4*7)+(3*6)+(2*5)+(1*9)=138 138 % 10 = 8 So 105776-59-8 is a valid CAS Registry Number.