Could you please explain in case we could perform any operations on newly included elements using xsl? To explain using an example: if we have the following input file <?xml version="1.0" encoding="UTF-8"?> <top> <Results> <a>no</a> <b>10</b> <c>12</c> <d>9</d> </Results> <Results> <a>Yes</a> <b>8</b> <c>50</c> <d>12</d> </Results> </top> We need the final result as <?xml version="1.0" encoding="UTF-8"?> <top> <Results> <a>no</a> <b>10</b> <b_>10</b_> <c>12</c> <c_>12</c_> <d>9</d> <e_>11</e_> </Results> <Results> <a>Yes</a> <b>8</b> <b_>8</b_> <c>50</c> <c_>50</c_> <d>12</d> <e_>29</e_> </Results> </top> Where: b_ = b, c_ = c, & e_ = (b_ + c_)/2