Torque responds to either a longer arm or a larger force. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Base arm-force product
Lever arm 3 m times force 4 N gives torque 12 newton meters.
τ=3×4=12
Longer arm doubles torque
Lever arm 6 m times force 4 N gives torque 24 newton meters.
τ=6×4=24
Larger force also doubles torque
Lever arm 3 m times force 8 N gives torque 24 newton meters.