The CAS Registry Mumber 142730-60-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,2,7,3 and 0 respectively; the second part has 2 digits, 6 and 0 respectively. Calculate Digit Verification of CAS Registry Number 142730-60: (8*1)+(7*4)+(6*2)+(5*7)+(4*3)+(3*0)+(2*6)+(1*0)=107 107 % 10 = 7 So 142730-60-7 is a valid CAS Registry Number.