Using Parentheses
At times, you may want an expression evaluated differently from the normal order of evaluation. Using parentheses lets you control the order of evaluation. You should use parentheses if you have any doubts about the way the calculator will evaluate an expression.
Effect of Parentheses
Using parentheses enables you to give priority to operations within an expression. When you enclose a portion of an expression within parentheses, that portion is evaluated separately.Although some mathematics expressions often use parentheses to imply multiplication, the RPD-95 requires that you include the [ × ] key in the calculation. For example, you must enter 7( 3 + 5 ) as 7 × ( 3 + 5 ).
Example
Calculate 7 × ( 3 + 5 ).Procedure | Press | Display |
---|---|---|
Clear display | [ CLEAR ] | |
Begin pending multiplication | 7 [ × ] | |
Enter and evaluate parenthetical expression | [ ( ] 3 [ + ] 5 [ ) ] | |
Complete pending operation | 2 [ = ] |
If this expression were entered without parentheses, the AOS feature would complete the multiplication ( 7 × 3 ) before the addition ( + 5 ), producing an incorrect result of 26.
Levels of parentheses
You can use up to 15 levels of parentheses. This give you the capability to enter more complex expressions.Example
Calculate 2 × ( 2 × ( 2 × ( 2 × ( 2 × ( 2 + 3 ) + 2 ) + 2 ) ) ).Procedure | Press | Display |
---|---|---|
Clear display | [ CLEAR ] | |
Enter pending multiplications | 2 [ × ] [ ( ] 2 [ × ] [ ( ] 2 [ × ] [ ( ] 2 [ × ] [ ( ] 2 [ × ] | |
Enter ( 2 + 3 ) | [ ( ] 2 [ + ] 3 [ ) ] | |
Evaluate ( 2 × 5 + 2 ) | [ + ] 2 [ ) ] | |
Evaluate ( 2 × 12 + 2 ) | [ + ] 2 [ ) ] | |
Evaluate ( 2 × 26 ) | [ ) ] | |
Evaluate ( 2 × 52 ) | [ ) ] | |
Evaluate 2 × 104 | [ = ] |
It is not necessary to press [ ) ] when it is at the end of a calculation. Pressing [ = ] automatically closes all open parentheses, evaluates the expression in the proper order, and displays the end result. However, if you want to see the intermediate result of a parenthetical expression, you must use the [ ) ] key.
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