\
The expression is
.
\
\
Start at zero.
\
Move 15 units to the left.
\
From there, move 6 units to the right.
\
\
\
Rewrite the expression,
\
\
(Add:
)
\
The sum is
.
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=b736ab8db9f316d3bc248a704575ad6b.png\")
.![\"finding](\"/userfiles/image/Library/Pre_Algebra/finding_sum-15+6_number_line_diagram.gif\")
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step2.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=88342e9ca85beac4bf4e130ee1c98f39.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=6eccf6b78ca70d6937239da64f38c73c.png\")
(Add: ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=387223ca9c03da36697e6afe55c7ac02.png\")
)![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=cb935b919c47b547ad3434666b8fb386.png\")
.