The CAS Registry Mumber 167254-78-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,6,7,2,5 and 4 respectively; the second part has 2 digits, 7 and 8 respectively. Calculate Digit Verification of CAS Registry Number 167254-78: (8*1)+(7*6)+(6*7)+(5*2)+(4*5)+(3*4)+(2*7)+(1*8)=156 156 % 10 = 6 So 167254-78-6 is a valid CAS Registry Number.