The CAS Registry Mumber 90245-50-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,0,2,4 and 5 respectively; the second part has 2 digits, 5 and 0 respectively. Calculate Digit Verification of CAS Registry Number 90245-50: (7*9)+(6*0)+(5*2)+(4*4)+(3*5)+(2*5)+(1*0)=114 114 % 10 = 4 So 90245-50-4 is a valid CAS Registry Number.