The CAS Registry Mumber 61588-37-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,1,5,8 and 8 respectively; the second part has 2 digits, 3 and 7 respectively. Calculate Digit Verification of CAS Registry Number 61588-37: (7*6)+(6*1)+(5*5)+(4*8)+(3*8)+(2*3)+(1*7)=142 142 % 10 = 2 So 61588-37-2 is a valid CAS Registry Number.