title: How to perform subtraction between Text Field and Variable
body: <p>I am very new with ireport-5.6.0. </p>
  
  <p>I have one text field(<strong>Sanctioned_intake</strong>) and one i declare variable(<strong>ROPORT_COUNT</strong>)<strong>.Sanctioned_intake</strong> is nothing but total number of Student per Department and <strong>REPORT_COUNT</strong> is return total no of rows which is enter into the report </p>
  
  <p>For Example:</p>
  
  <p>Sanctioned Intake:140 (Total Student per Department)         </p>
  
  <p>Actual Admitted: 10 (Actual Admission Taking)       </p>
  
  <p>So Difference Should Be:</p>
  
  <p>Vacancy : 130(Remaining Vacancy )</p>
  
  <p>now my question is how to make difference between this two</p>
  
  <p>I declare One Variable </p>
  
  <p>and set the following properties</p>
  
  <p>variable class=java.math.BigDecimal<br>
  Calculation    Sum<br>
  Reset Type     Report<br>
  Variable Expression:   $F{sanctioned_intake}.substract($V{REPORT_COUNT})</p>
  
  <p>But i got this error</p>
  
  <pre><code>Error filling print... Error evaluating expression :      Source text : $F{sanctioned_intake}.substract$V{REPORT_COUNT} 
          net.sf.jasperreports.engine.fill.JRExpressionEvalException: Error evaluating expression :      
      Source text : $F{sanctioned_intake}.substract$V{REPORT_COUNT}  
      at net.sf.jasperreports.engine.fill.JREvaluator.evaluateEstimated(JREvaluator.java:327)  
  Caused by: groovy.lang.MissingMethodException: 
  No signature of method: java.lang.String.substract() is applicable for argument types: (java.lang.Integer) values: [1] 
  Possible solutions: substring(int), substring(int, int) 
  </code></pre>