The CAS Registry Mumber 126949-58-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,6,9,4 and 9 respectively; the second part has 2 digits, 5 and 8 respectively. Calculate Digit Verification of CAS Registry Number 126949-58: (8*1)+(7*2)+(6*6)+(5*9)+(4*4)+(3*9)+(2*5)+(1*8)=164 164 % 10 = 4 So 126949-58-4 is a valid CAS Registry Number.