Computer for calculating compound interest

• US 4,486,849 A
• Filed: 09/28/1982
• Issued: 12/04/1984
• Est. Priority Date: 03/19/1976
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Harigaya, Isao, Yamataka, Akihiro
• Primary Examiner(s): Krass, Errol A.
• Application Number:
  US06/426,078
• Time in Patent Office: 798 Days
• Field of Search: 364/408, 364/709, 364/715
• US Class Current: 708/134
• CPC Class Codes: G06F 15/02 manually operated with input through keyboard and computation using a built-in program, e.g. pocket calculators
• CPC Class Codes: G06F 15/025 adapted to a specific application
• CPC Class Codes: G06F 7/491 Computations with decimal numbers radix 12 or 20. G06F7/4824 takes precedence
• CPC Class Codes: G06Q 40/12 Accounting

Abstract

A computer capable of performing the compound interest operation of (1+i)ⁿ where i=interest rate and n=term.

Claims

1. A computer comprising:

a keyboard including an instruction key for instructing the initiation of a compound interest computation, and including a plurality of numeric keys for entering numeric data into the computer;

memory means responsive to first and second operations of said instruction key for respectively storing first status information and second status information;

first controlling means coupled to said memory means for processing numeric data representing an interest rate i which is entered into the computer through said numeric keys as a result of storing said first status information in said memory means;

second controlling means coupled to said memory means for processing numeric data representing a time period n which is entered into the computer through said numeric keys as a result of storing said second status information in said memory means; and

means for controlling the execution of said compound interest computation in accordance with the term (1+i)ⁿ utilizing said numeric data representative of said interest rate and said numeric data representative of said timer period processed respectively by said first and second controlling means.

2. A computer as set forth in claim 1, wherein said first controlling means comprises means for replacing said first status information stored in said memory means with said second status information.

3. A computer as set forth in claim 1, wherein said second controlling means comprises means for replacing said second status information with said first status information.

4. A computer as set forth in claim 1, wherein said first controlling means comprises means for executing a logarithmic operation on the result obtained from the addition of one to said numeric data.

5. A computer as set forth in claim 4, wherein said second controlling means comprises means for executing the product of said numeric data representative of said time period and the result of said logarithmic operation.

6. A computer comprising:

input means including a compound interest rate instruction key, and a plurality of numeric keys for entering numeric data into the computer;

memory means for storing information representative of a first-time and a second-time operation of said compound interest rate key; and

processing means, responsive to entry of said numeric data, for processing said numeric data as an interest rate i, when said stored information is representative of the first-time operation, and for processing said numeric data as a time period n, when said stored information is representative of the second-time operation, and wherein said processing means processes a compound interest computation in accordance with the term (1+i)ⁿ by utilizing said entered numeric data representing said time period and said entered numeric data representing said interest rate.

7. A computer as set forth in claim 6, wherein said processing means includes means for changing said information of said means when said compound interest rate key operation is identified as the first-time key operation.

8. A computer as set forth in claim 7, wherein said processing means includes means for storing a first result obtained from processed numeric data representing said time period and a second result obtained from processed numeric data representing said interest rate.