If you have used 12% of the gas in your tank, the percentage of gas that remains in the tank can be calculated by subtracting the used percentage from 100%.

$\text{Percentage remaining} = 100\% - 12\%$

$\text{Percentage remaining} = 88\%$

So, 88% of the gas remains in your tank.

Would you like more details or have any other questions?

Here are 5 related questions for further exploration:

1. How do you calculate the remaining percentage if you've used a different amount, say 25%?
2. If your gas tank has a capacity of 50 liters, how much gas is left after using 12%?
3. How would the calculation change if you were to fill up the tank again after using 12%?
4. What percentage of gas would remain if you used 50% of your tank?
5. How can you calculate the remaining gas if you only know the number of miles driven?

Tip: To find the remaining percentage of any quantity, subtract the used percentage from 100%.