TR=P+Q \mathrm {TR=P+Q}TR=P+Q
TR=PQ \mathrm {TR = \frac{P}{Q}}TR=QP
TR=P×Q \mathrm {TR=P \times Q}TR=P×Q
TR=ΔPΔQ \mathrm {TR = \frac{\Delta P}{\Delta Q}}TR=ΔQΔP