**TI-15: Memory and Hidden Memory Arithmetic**

Many thanks to
Bob Patton, a fellow HP calculator enthusiast, who sent me this
information. One of the door prizes I
won from HHC 2016 was a TI-15 calculator which Patton donated. (I also previously purchased an HP 32
SII).

A link to my
previous retro review (October 2016): http://edspi31415.blogspot.com/2016/10/review-texas-instruments-ti-15.html

**Storing Numbers in Memory: A Unique Way**

I don’t think I
ever seen this storage sequence like the one that is presented in the
TI-15. Almost all calculators have a
sequence as such: ([2

^{nd}/Shift]) [ STO ] ([register/variable]). However to store numbers in memory on the TI-15, the sequence is [ = ] [ >M ] [ = ].
For example, to
store 100 in memory, I would press 100 [ = ] [ >M ] [ = ].

To recall
numbers from memory, press [MR/MC]. If
this key is pressed twice, the memory is cleared.

**Hidden Talent: Memory Arithmetic**

Patton sent me
the information of this neat undocumented feature of memory arithmetic. The following sequences are:

[ = ] [ M> ]
[ + ]: Add number to memory M

[ = ] [ M> ]
[ - ]: Subtracts number from memory M

[ = ] [ M> ]
[ * ]: Multiplies number to memory M

[ = ] [ M> ]
[ ÷ ]: Division, M ÷ number

[ = ] [ M> ]
[ Int÷ ]: Integer Division, int(M ÷ number)

Press [MR/MC]
to recall the result.

**Example**

Store 100 to
memory:

100 [ = ] [
>M ] [ = ]

Add 10 to
M. (Result: 110)

10 [ = ] [
>M ] [ + ]

Subtract 10
from M. (Result: 100)

10 [ = ] [
>M ] [ - ]

Multiply 10 to
M. (Result: 1,000)

10 [ = ] [
>M ] [ * ]

Divide
M/10. (Result: 100)

10 [ = ] [ >M
] [ ÷ ]

Integer Division. Int(M/6) (Result: 16)

6 [ = ] [ >M
] [ Int÷ ]

Special thanks
to Bob Hutton!

Eddie

This blog is
property of Edward Shore, 2017.

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