Double the Addition Fun!

I began introducing my first graders to two-digit addition.  To start the lesson I sat the kiddos down explained that in the past, we have been working with adding single-digit numbers.  I asked the students, “Why do we call these numbers single-digit?” 

After some discussion, I told them that we would be learning about double-digit addition.  The students brainstormed about what a double-digit number looks like prior to us going into a discussion about place value.

I explained to the students that place value helps keep all the numbers in order, the same way we keep order in our lunch line.  We practiced identifying the tens and ones place with red and green markers, which would help lead into the second part of the lesson.

Next, the kiddos and I talked about breaking down double-digit numbers such as 23 really meaning 2 tens and 3 ones (20+3=23).  We tested this theory with concrete manipulatives such as base-ten blocks and a map to guide us through computation.

I then moved to a semi-concrete model by using base-ten blocks as a supplemental aid for students to reference during computation and check for reasonability at the end of their problem.   I created a double-digit-addition map which helps students separate the ones and tens place, while also using color to indicate where to start and stop while adding the digits together.

The students loved using the dry-erase markers on their maps!  After some practice with our maps, I will eventually move the students into abstract models by taking away the manipulatives and the addition map.

Take Care,

Ms. Vince