The CAS Registry Mumber 724790-39-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 7,2,4,7,9 and 0 respectively; the second part has 2 digits, 3 and 9 respectively. Calculate Digit Verification of CAS Registry Number 724790-39: (8*7)+(7*2)+(6*4)+(5*7)+(4*9)+(3*0)+(2*3)+(1*9)=180 180 % 10 = 0 So 724790-39-0 is a valid CAS Registry Number.