<s>
The	O
HP-22	B-Device
was	O
a	O
finance-oriented	O
pocket	O
calculator	B-Application
produced	O
by	O
Hewlett-Packard	O
between	O
1975	O
and	O
1978	O
.	O
</s>
<s>
It	O
was	O
designed	O
as	O
a	O
replacement	O
for	O
the	O
short-lived	O
HP-70	O
,	O
and	O
was	O
one	O
of	O
a	O
set	O
of	O
three	O
calculators	B-Application
,	O
the	O
others	O
being	O
the	O
HP-21	B-Device
and	O
HP-25	B-Device
,	O
which	O
were	O
similarly	O
built	O
but	O
aimed	O
at	O
different	O
markets	O
.	O
</s>
<s>
As	O
with	O
most	O
HP	O
calculators	B-Application
then	O
and	O
now	O
,	O
the	O
HP-25	B-Device
used	O
RPN	O
entry	O
logic	O
,	O
with	O
a	O
four-level	O
stack	O
.	O
</s>
<s>
Its	O
principal	O
functions	O
were	O
(	O
1	O
)	O
time	O
value	O
of	O
money	O
(	O
TVM	O
)	O
calculations	O
,	O
where	O
the	O
user	O
could	O
enter	O
any	O
three	O
of	O
the	O
variables	O
and	O
the	O
fourth	O
would	O
be	O
calculated	O
,	O
and	O
(	O
2	O
)	O
statistics	O
calculations	O
,	O
including	O
linear	B-General_Concept
regression	I-General_Concept
.	O
</s>
<s>
A	O
shift	B-Device
key	I-Device
provided	O
access	O
to	O
functions	O
whose	O
legends	O
were	O
printed	O
on	O
the	O
faceplate	O
above	O
the	O
corresponding	O
keys	O
.	O
</s>
<s>
A	O
version	O
adapted	O
to	O
support	O
an	O
additional	O
backward-facing	O
display	O
manufactured	O
by	O
Educational	O
Calculator	B-Application
Devices	O
named	O
EduCALC	O
22GD	O
existed	O
as	O
well	O
.	O
</s>
