The CAS Registry Mumber 11137-48-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,1,1,3 and 7 respectively; the second part has 2 digits, 4 and 8 respectively. Calculate Digit Verification of CAS Registry Number 11137-48: (7*1)+(6*1)+(5*1)+(4*3)+(3*7)+(2*4)+(1*8)=67 67 % 10 = 7 So 11137-48-7 is a valid CAS Registry Number.