The CAS Registry Mumber 1570321-40-2 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,5,7,0,3,2 and 1 respectively; the second part has 2 digits, 4 and 0 respectively. Calculate Digit Verification of CAS Registry Number 1570321-40: (9*1)+(8*5)+(7*7)+(6*0)+(5*3)+(4*2)+(3*1)+(2*4)+(1*0)=132 132 % 10 = 2 So 1570321-40-2 is a valid CAS Registry Number.