The CAS Registry Mumber 1242248-76-5 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,2,4,2,2,4 and 8 respectively; the second part has 2 digits, 7 and 6 respectively. Calculate Digit Verification of CAS Registry Number 1242248-76: (9*1)+(8*2)+(7*4)+(6*2)+(5*2)+(4*4)+(3*8)+(2*7)+(1*6)=135 135 % 10 = 5 So 1242248-76-5 is a valid CAS Registry Number.