The CAS Registry Mumber 7350-51-8 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,3,5 and 0 respectively; the second part has 2 digits, 5 and 1 respectively. Calculate Digit Verification of CAS Registry Number 7350-51: (6*7)+(5*3)+(4*5)+(3*0)+(2*5)+(1*1)=88 88 % 10 = 8 So 7350-51-8 is a valid CAS Registry Number.