Revert "Creación de función resta"

This reverts commit e9dc6a48eea84ba9ebd9e95a1c32de6b6ceb64ed.
Revert "Revert "Creación de función resta""

This reverts commit 8d3e42100c0d4be34340bae7dbc3ad080caade78.
Revert "Revert "Revert "Creación de función resta"""

This reverts commit 60490d9438948cac88ecdc417765d4e64f5fb4f0.