If 1-3+4=100, 4-6+9=999 and 2-6+7=879 then 3-3+6=???

Question

If
1-3+4=100,
4-6+9=999,
2-6+7=879
then
3-3+6=???

Answer 1

Answer is 220
By solving the equation, we got to know each no. assigned to a new value like 100, 999, and 879:
1-3+4=2
2=100 --> (A)
4-6+9=7
7=999 --> (B)
2-6+7=3
3=879 --> (C)
3-3+6=6, but we don't have the value of 6.
To find 6 value, Using (A), (B), and (C) equation;
6=2+7-3=100+999-879=220
So 3-3+6 = 6 = 220.
I preferred to use this way, so that I could use all three (A), (B) & (C) equations.
The other way is:
6 = 2+2+2 = 100+100+100 = 300.
Similarly there are many ways.