non-RPN calculators work. In Algebraic mode, you enter formulas
in traditional @expr{2+3} notation.
+@strong{Warning:} Note that @samp{/} has lower precedence than
+@samp{*}, so that @samp{a/b*c} is interpreted as @samp{a/(b*c)}. See
+below for details.
+
You don't really need any special ``mode'' to enter algebraic formulas.
You can enter a formula at any time by pressing the apostrophe (@kbd{'})
key. Answer the prompt with the desired formula, then press @key{RET}.