Added one sentence to say what a helper is #159

Author: John

guides/v3.4.0/templates/handlebars-basics.md

@@ -46,6 +46,8 @@ controllers and components.
 
 ### Helpers
 
+Ember Helpers are functions that can compute values, and can be used in any template.
+
 Ember gives you the ability to [write your own helpers](../writing-helpers/), to bring a minimum of logic into Ember templating.
 
 For example, let's say you would like the ability to add a few numbers together, without needing to define a computed property everywhere you would like to do so.