HP HP-20S - Page 25

The HP-20S uses a system of operator priority to evaluate expres-
sions:
(exponentiation) Highest priority
(=]
(-] Lowest priority
The HP-20S calculates an intermediate result when the next operator
you enter has lower or equal priority. When the next operator has
higher priority, the HP-20S retains the previous number(s). For exam-
ple, in the calculation:
9(+]12(+]) 3 (=]
division has a higher priority than additon. Thus, the 9 and are
retained as a pending operation until the division is completed:
Keys: Display: Description:
9 12 (] 12.0000 Pressing [+] does not
add 9 + 12.
3 (=] 13.0000
Calculate 4 x 73 plus 5 x 72 plus 6.
4 7 7.0000 (*] has higher priority
than [x].
3 1,372.0000 Calculates 4 x 73.
5 5.0000 (x] has higher priority
than (+].
7 ¥¥) 7.0000 (*] has higher priority
than [x].
2 2_
1,617.0000 Adds 5 x 72 to 1,372.
6 (=] 1,623.0000 Completes the
calculation.
2: Arithmetic and Storage Registers 23