The CAS Registry Mumber 26076-15-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,6,0,7 and 6 respectively; the second part has 2 digits, 1 and 5 respectively. Calculate Digit Verification of CAS Registry Number 26076-15: (7*2)+(6*6)+(5*0)+(4*7)+(3*6)+(2*1)+(1*5)=103 103 % 10 = 3 So 26076-15-3 is a valid CAS Registry Number.