Hi Jim,

It's not a decimal point before the operator, it's a decimal point *after* the number. It's a way of overriding the current exact/approximate mode and explicitly stating that you want an approximate result (a numeric answer) rather than an exact result with integers.

You can toggle implicit exact/approximate mode by holding down right-shift and pressing enter.

If you're in algebraic mode (ALG displayed in the header) and in exact mode (= displayed in the header), try these:

1 / 2 [ENTER] -> '1/2'

1. / 2. [ENTER] -> '.5'

In the last example, you could have left the decimal point off either the 1 or the 2 and you'd have got the same result.

If you had tried the example from page 1-14 without the trailing decimal points, the calculator would have produced a non-approximate result, but the EXP() function must produce an approximate result, so the calculate instead asks you to confirm a switch to approximate mode.

If the calculator is in exact mode and you want an approximate answer, you can use (right-shift) ->NUM

1 / 3 [ENTER] -> '1/3' [->NUM] -> '.333333333333'

*Edited: 29 Jan 2011, 3:51 p.m. *