I came across an app that is designed to be used with fractions. Its Fraction Calculator Plus Free which has three keypads. The pad furthest to the left is for whole numbers. The keypad to the top right is for entering the numerator and the one found to the lower right is for the denominator.
It also allows a person to perform all the operations. It is nice because students get answers in both fraction and in decimals so they see it both ways. It is quite easy to use.
With an app like this, I wonder if its still necessary to make students learn all the rules of using fractions. The thing I keep noticing is simply that when students rely on a calculator to do all the calculations for them, they loose a certain amount of number sense. The number sense that tells them if the answer is reasonable.
There seems to be this general idea that if they did it on the calculator, the answer must be right. It never occurs to them they put in the information wrong so they didn't get the right answer. I've actually had students tell me that the answer can't be wrong because they did it on the calculator as if the calculator can perceive exactly what they want.
In the meantime, this calculator will allow students to check their work.