An inner tube for a bicycle has a diameter of 2 inches and measures about 82 inches along its circumference. What formula would you use to determine the numbers of cubic inches of air the inner tube can hold

What you are asking for is the volume of a torus, which is quite a complicated problem.

What grade level would this be?

If you want an approximation ....

Assume we cut the tube and stretch it into a long cylinder.
The the volume would be π(1^2)(82 = 82π
or appr. 578 cubic inches.

Is this answer sufficient?