The CAS Registry Mumber 103706-44-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,3,7,0 and 6 respectively; the second part has 2 digits, 4 and 4 respectively. Calculate Digit Verification of CAS Registry Number 103706-44: (8*1)+(7*0)+(6*3)+(5*7)+(4*0)+(3*6)+(2*4)+(1*4)=91 91 % 10 = 1 So 103706-44-1 is a valid CAS Registry Number.