The CAS Registry Mumber 5700-43-6 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 5,7,0 and 0 respectively; the second part has 2 digits, 4 and 3 respectively. Calculate Digit Verification of CAS Registry Number 5700-43: (6*5)+(5*7)+(4*0)+(3*0)+(2*4)+(1*3)=76 76 % 10 = 6 So 5700-43-6 is a valid CAS Registry Number.