Photon count drives packet energy across a fixed budget. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Photon packet energy is counted against a budget

The toy photon energy is fixed; only the packet count changes.

m=EmaxEpacketm=E_{\max}-E_{\text{packet}}
Below energy budgetOne photon leaves unused energy budget.singletotal

Three packet counts bracket the energy budget

The middle row uses the whole budget. The final row exceeds it.

NEpacketmgate166pass2120pass3186fail\begin{array}{c|c|c|c}N&E_{\text{packet}}&m&\text{gate}\\1&6&6&\text{pass}\\2&12&0&\text{pass}\\3&18&-6&\text{fail}\\\end{array}
Energy boundaryTwo photons exactly use the budget.singletotal

The three-photon packet is over budget

The helper computes the total energy first; the lesson gate only compares it with the budget.

m=6failm=-6\quad \text{fail}
Over energy budgetThree photons exceed the budget.singletotal