Stress is a quotient, so scaled force-area pairs can land on the same value. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
A different force-area pair can give the same stress
Force 6 N over area 2 square meters gives stress 3 Pa.
σ=AF=2m26N=3Pa
A different force-area pair can give the same stress
Force 9 N over area 3 square meters gives stress 3 Pa.
σ=AF=3m29N=3Pa
A different force-area pair can give the same stress
Force 12 N over area 4 square meters gives stress 3 Pa.