You're asking about a fuel mixture, likely for a small engine like a lawnmower or generator. Here's how to figure out the right amount of oil:

Understanding the Mixture

A 100:1 mixture means that for every 100 ounces of gasoline, you add 1 ounce of oil.

Converting to Gallons

* There are 128 fluid ounces in 1 gallon of gasoline.

* To make a 100:1 mixture with a gallon of gas, you'd need 128 ounces / 100 = 1.28 ounces of oil.

Important Note: Always refer to your engine's owner's manual for the specific fuel mixture recommendation. Using the wrong mixture can damage your engine.