Show • between letters in the input box
Show • between letters in the input box.
So when for example when the formula b^2 - 4 • a • c is shown in the input box, the students just have to substitute the letters with numbers without the need to also write • between the numbers.
If the students don’t do this, the program will stall.
As an alternative, you could make a error-message saying that there have to be placed some operation signs between the numbers so that the program won’t stall and the students become aware of the cause and what to change and remember next time.
But of cause it would be easier for the students with the first solution.
A third alternative would be to make it possible to convert a string to a function without the expression is reduced. That would also make it possible to use input boxes for this purpose without the students have to delete the content of the input box before writing a new input and without having a content that can misguide the students.