Our Excel Math curriculum also reflects real-world usage. We don't create problems in imaginary worlds (Bikini Bottom where SpongeBob Squarepants lives, or Lazy Town where Spartacus saves the day, or the Big Oak Tree where Mr. Squirrel keeps his acorns).
Real life is more interesting, harder to predict, and full of fascinating math opportunities. Yesterday I learned that my local natural gas utility creates an energy factor that reflects the heat content of gas used in 6 zones around the county. They adjust our bills accordingly.
Here's a GAS SERVICE table showing recent natural gas costs. The column headings are:
- Baseline = a reasonable amount for an average household (available at a low price)
- Non-Baseline = any usage over baseline (Swimming Pool Heater, long showers, etc.); charged at a higher cost
- GTC means Gas Transportation Cost which reflects getting the gas to us
- GPC means Gas Procurement Cost which is what they pay for the gas
- Total cost is the combination of cost plus shipping (pipeline, etc)
Once the procurement and transportation are taken care of, the energy content is measured and adjusted by the therm multiplier, as shown in the GAS ENERGY CHARGE table below:
When these things are combined, you get a natural gas bill. Here's a sample:
The amount we pay is a total of the Gas Service and the Gas Energy Charge. This particular bill is more complex than usual because the Gas Energy Charge changed in the middle of the month.
This is not too difficult for elementary math, even if it looks daunting at first glance. If you think this is complicated, take a look at your electricity bill!