The CAS Registry Mumber 58142-01-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,8,1,4 and 2 respectively; the second part has 2 digits, 0 and 1 respectively. Calculate Digit Verification of CAS Registry Number 58142-01: (7*5)+(6*8)+(5*1)+(4*4)+(3*2)+(2*0)+(1*1)=111 111 % 10 = 1 So 58142-01-1 is a valid CAS Registry Number.