It's 7 #s long
Hint 1: The first number times the last number will always equal the last number (first*last=last)
Hint 2: fourth number minus the last number equals the third number (fourth-last-third)
Hint 3: first number - sixth number equals fourth number
Hint 4: a two part hint first minus second will equal x (first-second=x) then x times last equals fourth (x*last=fourth)
Hint 5: Third plus last equals fourth (third+last=fourth)
Hint 4:first plus second equals third (first+second=third)
Hint 3:fifth number plus the last number will equal the sixth (fifth+last=sixth)
Hint 2:The last number plus the second number will equal the fifth number (last+second=fifth)
7 digit number
ABCDEFG
1. A*G=A => G=1
2. D-G=C => D-1=C => D=C+1
3. A-F=D => D=A-F
4. Let x=A-B, G*x=D => 1*x=D => D=A-B
5. C+G=D => C+1 = D (same as hint 2)
6. C=A+B
7. E+G=F => E+1 = F
8. G+B=E => B+1 = E
Now try to solve for A, B, C, D, E and F (G=1)