SWBAT fluently identify 2 addend combinations of 10. SWBAT solve a problem in which the total and one part are known.

A twist will be added to the traditional game of Go Fish as students work on building their fluency with complement of ten facts.

5 minutes

I start by asking the kids to stand in a circle on the carpet.

*"You are going to play a game of POP. You will start with the number 101 and you will count up until you get to the last number 120."*

This is a game that was introduced in a lesson at the beginning of September and has been played throughout the school year. To see a full description of this activity, please see the linked lesson.

I am choosing this number range because it is expected that first grade students can count up to 120. Students tend to get stuck on the 109 to 110 transition and I often will hear, "109, 200." The CCSS expect that 1st grade students can "count to 120, starting at any number less than 120 (CCSS.Math.Content.1.NBT.A.1)." If this error occurs, I take out the place value blocks and model why 109 is written the way it is and then add one more one cube, make the trade, and then ask what the next number is and who do we write it. This offers a great visual for this misconception/error.

20 minutes

Advanced Preparation: You will need a set of number cards or playing cards for each team. To play the game you will only use the 1-9 cards. The rest should be discarded for this activity.

*"How many of you have played Go Fish? We are going to play a similar game today but instead of finding matches you will be looking for pairs that make 10. You start by dealing out 5 cards to each player and then put the remaining cards face down on the table. On your turn, you should look to see if you have any cards (using only 2 cards) in your hand that can make ten. If you do, you pair them up and put them down on the table. You then can pick two new cards up from the pile that is face down on the table. If you can't make 10, on your turn, you can ask the other person if they have a card that you would need. For example, if I had a 3, what card would I want to ask for?*

*Each time I get a new card, I check to see if I can make 10 with that card and a card that's already in my hand. If I can, I out the pair down. If I can't, then my turn is over. If I run out of cards, I can pick two new cards from the deck."*

*"When you have run out of cards, the game is over. You then use the recording sheet (see section resource) to record each combination you collected to make ten. Let's play a sample round, as a class, to make sure everyone understands how to play."*

In this activity, I am asking students to make sense of quantities and their relationships in a problem situation (**CCSS.Math.Practice.MP2**). The students are developing an understanding that if I have a 4, I will always need a 6 to make 10.

25 minutes

Students now team up and play the game that was just described in the previous section. I will choose the partners in my class to maximize efficiency and productivity.

I would have extra recording sheets available for group that finish early. It is important to have the students recording their combinations that they make. The expectation is that students can represent their thinking with a written equation (**CCSS.Math.Practice.MP4**)

10 minutes

I want to end this part of the lesson with a discussion about the strategies students used to find the complements of 10. Strategies would include using cubes, counting on, or using a known fact.

**"Let's look at what I wrote on the board. Four add what equals ten? Who can tell me how you would solve this?"**

While students were playing the game (earlier in the lesson), I would have identified which students were using specific strategies. This way, I could call on students to model each specific strategy. I specifically call on students using the cubes 1st, then the counting on strategy, and the the known fact. The reason is, I want to end the discussion with the students hearing the idea of known facts last. I want this idea to be what they walk away with.

As students explain their approach, you could illustrate it on the white board.

It is important to focus on the strategies that students are using. The CCSS expect that first graders can "add and within 20, demonstrating fluency for addition within 10 (CCSS.Math.Content.1.OA.C.6)." By modeling the different strategies, you can push them along the continuum and work toward fluency by building the concept and knowledge of "known facts."

10 minutes

Students play in teams of two (one team of three is you have an odd amount). You will need a ten sided die for each team. These can be ordered from any school supply company. The die is numbered 0-9.

*"We are going to finish today's math class with another game that works on building your knowledge of complements of 10 and knowing them with fluency. You will sit across from your partner. One of you will roll the die and look at the numbered rolled. You will then call out the number that complements the rolled number to make 10. For example, if I rolled a 4, I would then say '6'. Your partner will then have to state the number that goes with 4 to make 10. They can check if they are correct by looking at the die that you rolled. You then switch roles and play again."*

There is a video in the section resource that models this game being played.