| Department of Mathematics |
On the TI-83 and 84, There is a little script i above the decimal point. You may need to change MODE from Real to a+bi.
The TI-85 and TI-86 use a different notation. Rather than a+bi, they use (a,b). For example, to enter (4+i)+(5+i), type (4,1)+(5,1). The calculator will give (9,2), i.e. 9+2i, as the answer.