The CAS Registry Mumber 56774-70-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,6,7,7 and 4 respectively; the second part has 2 digits, 7 and 0 respectively. Calculate Digit Verification of CAS Registry Number 56774-70: (7*5)+(6*6)+(5*7)+(4*7)+(3*4)+(2*7)+(1*0)=160 160 % 10 = 0 So 56774-70-0 is a valid CAS Registry Number.