To Designate Input and Output Regions
1. In a worksheet, select one or more math regions. To create input regions, select regions that contain a definition. To create output regions, select regions that contain a result.
2. On the Input/Output tab, in the Integration group, click Assign Inputs or Assign Outputs. PTC Mathcad designates the region according to your selection.
3. To view all input and output regions in the worksheet, use the following methods:
◦ Click Show As List. The Input/Output Designation window opens. The inputs and outputs are listed in two tables.
◦ Click Show in Worksheet. All the regions you designated are displayed with borders and the string In or Out appears above each region.
4. To un-designate a region, click Show As List. In the Input/Output Designation table, click 
next to the region you want to un-designate.
next to the region you want to un-designate.Alternatively, select the designated region and click Assign Inputs or Assign Outputs on the Input/Output tab.
When you remove a region that contains several inputs, all inputs are removed.
5. To edit a region alias, click its name in the table and type the new name in the Alias column.
When you click a name in the table, the corresponding region is highlighted in the worksheet.