The CAS Registry Mumber 70547-52-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,0,5,4 and 7 respectively; the second part has 2 digits, 5 and 2 respectively. Calculate Digit Verification of CAS Registry Number 70547-52: (7*7)+(6*0)+(5*5)+(4*4)+(3*7)+(2*5)+(1*2)=123 123 % 10 = 3 So 70547-52-3 is a valid CAS Registry Number.