Problem Solver has with simple equation

[Nick1941]

There is an equation in chemistry that relates the energy of an electron in an orbital with quantum number n in a hydrogen atom. The equation is E_n = E_n1/(n^2) with E_n1 = -2.18E-18. When I compute this on the Home screen with, say, n=4, it immediately displays the result: -1.3625E-19. However, when I enter that equation in the solver, and in the numbers screen have -2.18E-18 in the En1 field and 4 in the n field, and move to the En field and select Solve, the calculator battery symbol changes to an hourglass like it's crunching through a very complex calculation. After a few minutes, I just aborted the calculation. Why does the Solver app have such a problem with such a simple equation?

Additional information: The Solver seems to have problems with negative exponents greater than or equal 10. If I set X = 2.2E-9 and n = 4 and set up the equation Y = X/(n^2), when I click Solve, it immediately solves the problem. However, if I set X = 2.2E-10 and run the same equation, the Solver gets locked up in an hourglass situation and can't solve the problem in a reasonable amount of time. BTW, I have found the same problem using the Virtual Calculator.