The finite direction table flips when the current arrow reverses. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Reversing current keeps the force magnitude
The same field 2, current 3, and length 4 still give 24 newtons.
2×3×4=24
Only the finite force direction flips
The reversed current changes the direction table result from up to down, not the value 24.