The CAS Registry Mumber 152694-88-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,5,2,6,9 and 4 respectively; the second part has 2 digits, 8 and 8 respectively. Calculate Digit Verification of CAS Registry Number 152694-88: (8*1)+(7*5)+(6*2)+(5*6)+(4*9)+(3*4)+(2*8)+(1*8)=157 157 % 10 = 7 So 152694-88-7 is a valid CAS Registry Number.