Which calculator are you using? Knowing this will help diagnose the problem and fix it.
I assume he means our web2 calc :)
You have to do it the old fashion way.
\(4\frac{1}{4}-2\frac{7}{9}\)
(4+1/4)-(2+7/8)=
(4+1/4)-(2+7/8) = 1.375 The calc actually did show the improper fraction answer as well.
But if you need a fraction calculator I suggest you do not use this one.