Question:
Solve 143 + 678 = 207*z - 7 for z..

Answer:
4

Question:
Solve 497 = 140*r - 392 - 651 for r..

Answer:
11

Question:
Solve -3 - 27 = 10*m for m..

Answer:
-3

Question:
Solve 100 = 10*f + 50 for f..

Answer:
5