Here's how you do it: First get on your calculator, a normal one, and press "1" on your calculator, followed by the "+" (plus) sign. The "1" symbolizes the whole number of the mixed fraction. Input the numerator, or the top number of the fraction. For this example, it would be the number five. Press the "÷" (divided by) button and enter the denominator, which would be "7", if following the example of 1 and 5/7. Your screen should read "1+5/7."
Read more: http://www.ehow.com/how_8353151_type-mixed-fraction-ti83-plus.html#ixzz2mSlphXYA
Hope it helps! XD
P.S: the following instructions are for the TI-83 Plus!
