The CAS Registry Mumber 3572-56-3 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 3,5,7 and 2 respectively; the second part has 2 digits, 5 and 6 respectively. Calculate Digit Verification of CAS Registry Number 3572-56: (6*3)+(5*5)+(4*7)+(3*2)+(2*5)+(1*6)=93 93 % 10 = 3 So 3572-56-3 is a valid CAS Registry Number.