The CAS Registry Mumber 65448-10-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,5,4,4 and 8 respectively; the second part has 2 digits, 1 and 0 respectively. Calculate Digit Verification of CAS Registry Number 65448-10: (7*6)+(6*5)+(5*4)+(4*4)+(3*8)+(2*1)+(1*0)=134 134 % 10 = 4 So 65448-10-4 is a valid CAS Registry Number.