Update _index.md (#20)

content/teachers/learn/planner/_index.md

@@ -8,7 +8,7 @@ contributors: ["rossdotparker"]
 
 ### Introduction
 
-The Planner is one of Gibbon's key tools for teachers and departments. It support a collaborative planning process that stretches from design through to delivery and then ongoing improvement. In addition, it provides a key way for teachers to communicate learning content with students, parents and colleagues.
+The Planner is one of Gibbon's key tools for teachers and departments. It supports a collaborative planning process that stretches from design through to delivery and then to ongoing improvement. In addition, it provides a key way for teachers to communicate learning content with students, parents and colleagues.