Lesson: Introduction to Addition

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Lesson Objective

To introduce students to the meaning of the addition sign and equal sign. SWBAT identify the addends, equal sign, addition sign, sum, and solve an addition problem.

Lesson Plan

Building Number Sense (5 minutes)


Counting Circle (create a circle of shapes drawn on the white board or chart paper, student groups of 4 to 5 students each choose a shape to start on, teacher points to that shape, students receive a value to count to by increments (“Count to 20 by 2’s”), teacher points to each shape around the circle as the whole class counts for the group, if the count ends on a triangle that groups gets a point if it ends on another shape, the shape is erased and no points are awarded, another group is now up)


Name Collection Box (Use the number from the day of school, write number in top left of box, write different “names” for that number in box; coins, base ten blocks, tallies, pictures, words, etc.)


Mental Math Fluency (5 minutes)


Pepper with place value (all students stand, write numbers on board and ask place value, when student answers correctly they sit and “earn their seat”, ex: the number is 45 how much is the 4 digit worth? Or What place value is the 5 in)


Problem of the Day  (7 minutes)


Terrance buys 5 zhu zhu pets, Julia buys 4 zhu zhu pets, how many zhu zhu pets did they buy altogether?




How did you solve this problem?


Teacher or Student (TS): Well we knew that Terrance bought 5 and Julia bought 4. So if they both bought that many we put those numbers together. I can count on my fingers, draw tallies, or use unifix cubes to show that when we add 5 to 4 it is 9.


How did you know that you were going to be putting the numbers together?


TS: When you buy something you are getting/adding it NOT losing it, also the word problem ends with a key vocab word “altogether” which lets us know it is adding up


How did you combine the numbers?


Student (S): I counted on my fingers, I made tallies, I used unifix cubes, etc.


Teacher (T): Well there is a special way we can show when numbers are being combined.






Mini Lesson              (12 minutes)


(With all questions you may elicit answers from class or give answer depending on time, class, and teaching style. I prefer to have kids drive answers and all the answers written are the conclusions I will drive student conversations to. But I still keep it very teacher driven as this is the “I” do)


What is this [draw the + sign on board]?


T: It is an addition sign, it shows when things are being put together, combined. Go over vocab for combining: more, adding, plus, combined with, and any more student added ones. (write the addition sign on a “vocab” chart and write “+ is an addition sign it shows we are combining numbers.” )


Why do we use an addition sign?


TS: We use it to show that two numbers are being combined, added together. It shows we are adding more. So you know what to do with the answer.


What is this [draw the = sign on board]?


 TS: An equal sign.


What does it show?


 T: It is like a balance (take out a balance and demonstrate balancing it with unifix cubes if there is three on one side we need three on the other side to balance, place a note card on the base with a big equal sign on it). So the equal sign is a balance each side of it needs to be balanced. Add “= equal sign is a balance, both sides of the equal sign need to be worth the same amount”. So if there is 4 cubes on this side how many do I need on this side?


S: We need 4 unifix cubes on the other side.


T: Why?


S: We need 4 unifix cubes on the other side because we need to make both sides equal (the same), since one side has 4 we need 4 on the other side.


Stress this use of complete sentences and “because” answer format.




[Show two blue unifix cubes and 3 black unifix cubes.]


How many unifix cubes do I have in all?


T: Well I have 2 blue lets write that [draw two cubes with blue marker], and 3 black lets write that [draw 3 black cubes with black marker]. So are we combining/adding together our numbers?


S: Yes, we are adding the numbers together.


T: Correct, why?


S: We are adding the numbers because we are combining all the cubes together, adding them together.


T: So I’m now going to write the EQUATION for this problem. First I write one of the numbers [write 2] then write the…what sign are we using? Why?


T: Addition sign [write +] and lastly the equal sign [write =]. Who has seen this before?


S: I have seen that before.


T: Where have you seen that?


S: Last year, in math, on homework, on the computer, etc.


T: Great well who knows what this is called (point to the two)? It is called an addend both the two and three are our addends [add to the vocab chart that should have addition sign, equal sign, and addends on it at this point]


 What are we going to do with these two numbers (2 and 3)? How do you know?


 S: We are going to add the two numbers together, I know this because I see the + sign which means we are combining the numbers.


T: So lets combine them, how much is 2 plus 3? [draw tallies or circles or whichever you prefer the kids go to first] It is 5 so if there is five on this side of the equal sign how could we balance out the two sides?




S: By putting a five on the right side of the equal sign.


T: This five has a special name when we write an answer to an addition fact it is called a sum (add sum to vocab chart)


But what if the problem is =2+3?


TS: It’s the same, we still have five on one side of the equal sign so we need to balance the two sides and put 5=2+3.


Work Time (Zones, Independent, Group 30 minutes)


Independent work “we do”: Students will have whiteboards or notebook paper. Draw some pictures on the board of 3 blue circles and 5 red circles or 2 triangles and 1 square. Go through the problems figuring out how many shapes there are in each of them. Doing the first one and then releasing more steps to students as they become comfortable writing the numbers for each set, putting an addition sign and equal sign and balancing the two sides. Ask reinforcing questions: Why do we put a + sign, what does the = sign mean, how do you know we are combining the numbers?




Move from shapes to just writing two numbers 2 and 4, and asking students to combine them.




Group Work “You Do” (Math Zones): All groups (of 4 students each) plays addition build it. Students roll two six sided dice and then pull the two numbers in unifix or base ten cubes. Student rolls a 2 and a 3 then they pull two unfix cubes and three unifix cubes, they then write down the addition problem and solve it. Teacher is either working with a small group that has been targeted for individual instruction or circling, taking notes on students work and misunderstanding, also asking supporting questions. So why did you put an addition sign here? Why did you put a 6 on that side of the equal sign? (Because one side was 2+4 which is 6 so I had to balance both sides)






Math Reflection/Share (4 minutes)


(This is a time to share work and discuss critically a problem a student had or explain student work. Also this time can be used to ask a difficult question that takes the concept taught one more level up in bloom’s taxonomy)




Why is 2+7=10 wrong? Students write down answers in math notebooks or on a piece of paper using words, drawings, etc.


(It is wrong because each side of the equal sign are not balanced/equal. I know this because 2+7, shown by fingers, manipulatives, or drawings is 9 and the other side of the equal sign says 10. So how can we fix the problem? Change the 10 to a nine, change the 2 to a 3, or the 7 to an 8. Why is the problem now correct?  Both sides of the equal sign are balanced/equal)


1. What went well?


2. What would you change?


3. What needs explanation?


The direct translation of manipulative into equations was great for the students, kept them engaged and gave tangibility to addition sentence.


Forgot to play through game first with whole group for “addition build it”, explained and then released kids to groups, next time will play through game me vs. class for a couple of turns.


In general the question to “answer” format is to show a constructive lesson structure, pushing children down a path of thinking through good questions and pushing their thinking, lots of “whys” and “explain that more”. This scaffolding of their thinking and input allows them to guide lesson.






Lesson Resources

Math Unit 2 Day 1 Assessment and Answer Key   Assessment
Math Unit 2 Day 1 Building Number Sense Examples doc   Activity


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