fx-82MS fx-9860GII
On a Casio calculator you can enter a mixed fraction
G SHIFT ab/c
Example 1.
G G 3 SHIFT ab/c 1 ▷ 4 ▷ + 1 SHIFT ab/c 2 ▷ 3 EXE
but with the SET UP Frac Result d/c you get the answer
Example 2
To convert the mixed fraction 1½ to the decimal fraction 1.5
G 1 SHIFT ab/c 1 ▷ 2 EXE F↔D 1.5
Example 3
To calculate 2 1/2 = 5/2 = 2.5
G 2 SHIFT ab/c 1 ▷ 2 EXE F↔D 2.5