This is a great resource for primary grade teachers - a visual. It is a great transition from a tactile manipulative to a only paper-pencil - mental math.
This is also a helpful activity for students receiving special education - a visual for those kiddos to understand what they are doing to utilize doubles to learn their addition facts...double, then plus 1.
10 different versions - plus answer key (probably do not need an answer key, but included).
Hope the resource is helpful to your students!