HP HP-20S - Using Parentheses

If a calculation requires that operations be done in an order inconsis-
tent with operator priority (for example, addition before multi-
plication), use parentheses. You can use a maximum of five pending
operations.*
Using Parentheses
Use parentheses to group operations and to specify the order in which
they are performed.t For example, you can calculate:
9 + 12
3
by placing parentheses around the addition so that it is done before
the division:
Keys: Display: Description:
9 12 21.0000 evaluates expression
inside parentheses.
53[5 7.0000
Calculate —30 X V169 — 8:
85 — 12
30 (] 30.0000
85 85_
(=] 85.0000 prevents division of
30 by 85.
12 73.0000 evaluates expression
inside parentheses.
0.4110 Calculates 30 + 73.
* There are less than five pending operations available if you have more than four pending
left parentheses. For example, you can calculate 1 + 2 + 3 + 4 + (5 + 6.
T Closing parentheses at the end of the expression can be omitted. For example,
25 + (3 x (9 + 12 [=]is equivalent to 25 +~ (3 x (9 + 12)) (=].
24 2: Arithmetic and Storage Registers