The CAS Registry Mumber 1220993-44-1 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,2,2,0,9,9 and 3 respectively; the second part has 2 digits, 4 and 4 respectively. Calculate Digit Verification of CAS Registry Number 1220993-44: (9*1)+(8*2)+(7*2)+(6*0)+(5*9)+(4*9)+(3*3)+(2*4)+(1*4)=141 141 % 10 = 1 So 1220993-44-1 is a valid CAS Registry Number.