The CAS Registry Mumber 78249-07-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,8,2,4 and 9 respectively; the second part has 2 digits, 0 and 7 respectively. Calculate Digit Verification of CAS Registry Number 78249-07: (7*7)+(6*8)+(5*2)+(4*4)+(3*9)+(2*0)+(1*7)=157 157 % 10 = 7 So 78249-07-7 is a valid CAS Registry Number.