Answer :

the difference is
 
 302
-129
_____
 173
to prove this
  173
+129
_____
3+ 9 is 12 so the unity is 2 and you plus 1 to the tenth; 7 + 2 is 9 but if you plus the number that remained in the unity is 10 so the the tenth is 0 and you will plus 1 to the hungred, 1+1 is 2 but if you plus the 1 that remained in the tenth is 3, so if we put them all together it will be 302
i hope i helped you

The answer is -173. Its -173 because subtracting -302 and positive 129. Positive is bigger then negative so the positive goes first, but negative is deeper into negative number line so ur answer is most likely negative. Best I can explain lol...