The CAS Registry Mumber 134790-03-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,4,7,9 and 0 respectively; the second part has 2 digits, 0 and 3 respectively. Calculate Digit Verification of CAS Registry Number 134790-03: (8*1)+(7*3)+(6*4)+(5*7)+(4*9)+(3*0)+(2*0)+(1*3)=127 127 % 10 = 7 So 134790-03-7 is a valid CAS Registry Number.