Mathematics Homework Help

For each item in the excel sheet I have to find the wattage and
estimate monthly use for each one. Some items are already in watts, as
they were on the product. Then calculate the kWh per month per device.
Next I am to find out the average cost per KWh that I pay. The kWh for
February was 185kWh. The electrical cost was $32.52

Based on the KWh estimate and average electrical cost, determine the monthly cost expected.

Next
calculate monthly savings if you were to replace all incandescent
lighting to fluorescent bulbs. Determine how long it would take before
making the switch would cover the cost of bulbs.

This has to be done in excel and I am not familiar with inputting math equations in Excel. I attached the Excel sheet