The CAS Registry Mumber 103298-56-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,3,2,9 and 8 respectively; the second part has 2 digits, 5 and 6 respectively. Calculate Digit Verification of CAS Registry Number 103298-56: (8*1)+(7*0)+(6*3)+(5*2)+(4*9)+(3*8)+(2*5)+(1*6)=112 112 % 10 = 2 So 103298-56-2 is a valid CAS Registry Number.