HP 113394 User Guide - Page 91

Section 5: Additional Operating Features 91 The ~ key is also useful for checking the first number entered to make sure you keyed it in correctly. Before pressing the operation key or equals key, however, you should press ~ again to return the second number entered to the display. Regardless of how many times you press ~, the calculator considers the number in the display to be the second number entered. The Key in RPN Mode Occasionally you may want to recall to the display the number that was there before an operation was performed. (This is useful for doing arithmetic calculations with constants and for recovering from errors in keying in numbers.) To do so, press gF (LAST X). This section describes how to use gF in RPN mode. Arithmetic Calculations With Constants Example: At Permex Pipes a certain pipe fitting is packaged in quantities of 15, 75, and 250. If the cost per fitting is $4.38, calculate the cost of each package. Keystrokes (RPN mode) Display 15\ 4.38 § 75 gF § 250 gF § 15.00 4.38 65.70 75. 4.38 328.50 250. 4.38 1,095.00 Keys first quantity into calculator. Keys unit cost into display. Cost of a package of 15. Keys second quantity into display. Recalls unit cost - which was last number in display before § was pressed - into display. Cost of a package of 75. Keys third quantity into display. Recalls unit cost into display again. Cost of a package of 250. Another method for doing arithmetic calculations with constants is described on page 235. File name: hp 12c pt_user's guide_English_HDPMF123E27 Page: 91 of 275 Printed Date: 2005/8/1 Dimension: 14.8 cm x 21 cm