Using Grand Total and Independent Memory for Complex Invoicing
Introduction
Portable desktop (usually solar powered) calculators usually have at least two memory registers: independent memory (M) and grand total (GT).
Adding calculations to the independent memory by pressing the memory plus key [ M+ ].
Adding calculations to the grand total by pressing the equals key [ = ].
Invoice with Taxable and Nontaxable Items
We have an invoice that has items that are subject to sales tax, and items and services that are exempt from sales tax.
Take advantage of both the independent and grand total memories to calculate the total invoice.
Two approaches:
[ ON/C ] to clear the grand total memory
[ MC ] (or press [ MRC ] until the independent memory is cleared)
Method 1:
taxable items [ M+ ]
nontaxable items [ = ]
After finishing entering all the items, add sales tax:
[ MR ] [ × ] sales tax rate [ % ] [ M+ ]
Calculate the total invoice:
[ MR ] [ = ] [ GRAND TOTAL ]
Method 2:
taxable items [ = ]
nontaxable items [ M+ ]
After finishing entering all the items, add sales tax:
[ GRAND TOTAL ] [ × ] sales tax rate [ % ] [ = ]
Calculate the total invoice:
[ MR ] [ = ] [ GRAND TOTAL ]
The example will use Method 1.
An Example of an Invoice
Taxable Items:
$ 19.99
$ 39.96
$ 14.97
Nontaxable Items:
$ 109.00
$ 15.00
Sales Tax Rate: 9%
As long as you keep your designation of what memory registers are used, you can enter each item in any order. So both methods should work.
[ AC/ON ] [ MC ]
109 [ = ]
15 [ = ]
19.99 [ M+ ]
39.96 [ M+ ]
14.97 [ M+ ]
[ MR ] [ × ] 9 [ % ] [ M+ ]
[ MR ] [ = ]
[ GRAND TOTAL ]
Result: 205.6628
[ AC/ON ] [ MC ]
109 [ = ]
19.99 [ M+ ]
15 [ = ]
39.96 [ M+ ]
14.97 [ M+ ]
[ MR ] [ × ] 9 [ % ] [ M+ ]
[ MR ] [ = ]
[ GRAND TOTAL ]
Result: 205.6628
Invoice: $205.66
The calculators I used for this example are the Casio JF-100BM and Casio MC-12M Shop Calculator.
Eddie
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