Detecting and removing errors

 When solving problems one usually starts with some initial data and then using a set of steps calculates the final results.

 The input data  can be approximate , it may contain error also. Sometimes, the methods used for calculations are also approximate . The end result calculated  may show errors due to error in the input data or  error in the method or error in calculations.

 Before accepting the end result a check should be made to remove errors if any. The error in the input data can be because the data is wrong, incomplete, formatted incorrectly, outdated data , or  mistakes  made at time of entering data  .

 The flow of execution of the process ( complete calculations) can be watched by printing/observing the results of intermediate calculations and  by comparing with standard values. The values at certain selected points  can be changed and the effect can be observed on intermediate results as well as final result.

 In Excel the watch window makes it convenient to inspect, audit or confirm formula calculations and results in large spreadsheets. By using the watch window you do not need to repeatedly scroll or go to different parts of your worksheet. Simple way to put a cell on watch is ; right click on the cell, select ‘add watch’ from the displayed menu.

 All  formulas on the worksheet can be displayed and read quickly to check for error. Hold down ctrl key and press the key left to integer 1 on top left corner (  ̀  ). It will display all formulas on the worksheet.