Question 106472
a=b-1
b=c-1
d=e-1
e=f-1
b=d+e+f
.
d+e+f<10 So must be 1+2+3 or 2+3+4
b= 6 because if it were 9 then c would be 10
So, d+e+f=6
b=6
d=1 
e=2 
f=3
a=5
c=7
.
The number is: 567123
We didn't need the final clue.
Ed