\
The expression is
.
\
(Add:
)
\
(Cancel commen terms
)
\
The sum is 1.
![\"\"](\"/userfiles/image/steps_images/step1.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=d2a7f7d4f0e3bb14e4bb6df59cb1b96c.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=b86f4b2f5512855b8f2b4d9be9b4926f.png\")
(Add: ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=08f0fcc8abd1c230037085235939c32d.png\")
)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=346f89c32ec06cbd49e0ef8b566be67a.png\")
(Cancel commen terms) ![\"\"](\"/userfiles/image/steps_images/solution.JPG\")