The CAS Registry Mumber 1352999-72-4 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,3,5,2,9,9 and 9 respectively; the second part has 2 digits, 7 and 2 respectively. Calculate Digit Verification of CAS Registry Number 1352999-72: (9*1)+(8*3)+(7*5)+(6*2)+(5*9)+(4*9)+(3*9)+(2*7)+(1*2)=204 204 % 10 = 4 So 1352999-72-4 is a valid CAS Registry Number.