The CAS Registry Mumber 1204295-56-6 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,2,0,4,2,9 and 5 respectively; the second part has 2 digits, 5 and 6 respectively. Calculate Digit Verification of CAS Registry Number 1204295-56: (9*1)+(8*2)+(7*0)+(6*4)+(5*2)+(4*9)+(3*5)+(2*5)+(1*6)=126 126 % 10 = 6 So 1204295-56-6 is a valid CAS Registry Number.