See how running totals differ from rates of change with parcel deliveries: 120...

https://activecalculus.org/author/Running-Totals-Rates-of-Change

See how running totals differ from rates of change with parcel deliveries: 120 parcels by noon is a total, while 30 parcels per hour describes pace. The article shows how units and time windows—per hour, per day, or since opening—shape a dashboard number.