Sunday, December 14, 2014

Adding 3 Numbers

Adding 3 numbers is one of my favorite first grade math concepts. It's one of those things that students look at and say, "Woahh, that's hard" and then feel so proud of themselves when they can do it. I love that.

It can definitely be a tricky concept though so I wanted to write a blog post sharing my tips on how to make adding 3 numbers easy (and fun!) for your students as well as give you strategies you can teach your students to use.

Adding 3 numbers games and activities for math

I recommend starting in small groups or an "I do" whole group lesson using manipulatives and ten frames to show that no worries, kiddo mathematicians, it's easy.

For this small group activity, put 3 different colors of counting cubes into a container. Students reach into the bucket with one hand and grab a handful of counting cubes then sort them into 3 piles by color. Next, they put the cubes on their ten frames mat without leaving any spaces between the colors to show what number they made. Then, they write the number sentence they made and copy it onto their recording sheet, wipe off, and do it again! Having the different colored cubes and ten frames will really help them internalize the concept and, more importantly, understand the why 3+5+4 is 12. It's so important for them to understand what they're doing (adding 3 different amounts together) and what it actually means, not just be able to solve the problem. This activity is a great introduction to the concept that helps with just that!

I put the ten frame mat and recording sheet in sheet protectors so that they could be written on with dry erase markers. You could laminate them to get the same effect but I decided to use sheet protectors so I could change out the recording sheet really easy because I had 4 levels of the recording sheet to differentiate it as you can see below.

Anyone who knows me knows that I am all about differentiation. I think every student should be given the tools to learn any and every concept at their level. They can do anything as long as they're given the right tools! Kids care a lot about fair though so I like to provide the same activity.. just in different levels so that there's no that's not fair, why does Johnny get to do the cubes center?  type talk. So this station, for example, has 4 levels of recording sheets. For your lowest students, use the top left where it is only 4 problems and they also copy the ten frame's representation of the problem to further solidify the concept. The top right has a little more problems, bottom left a little more, and the bottom right even more. The beauty of the recording sheet being differentiated is that you can have kids of all different ability levels at your table sitting right next to each other doing the same activity and yet have it be leveled for each one. 

I recommend using this activity as a math station after they've done it in group because it provides a TON of practice and can be done over and over with different results every time. You could differentiate it by group OR have your whole class do the 2nd level and work their way up to the 3rd then the 4th. Tell them they're working their way up to the "hard level" and they'll eat it up. :)

Speaking of ten frames, I think they're a great strategy for adding 3 numbers. For those of you who use my math units, you'll notice the letter in the top right corner of the page to signify the level of the worksheet (A = below level, B = on level, C = above level). If you've used my other addition units, your students are hopefully ten frame ninja masters (hiii-yah!) by now so this should really help easing them into a new skill.

Another great math center using ten frames to help add 3 numbers is SOLVE IT!

For this center, students reach into the baggie and pull out a problem strip and place it in the space on their workmat. Then, they build it on the ten frame using 3 different cube colors and write their number sentence at the bottom. 

Best math games and math centers for teaching adding 3 numbers
It's very similar to the Grab Sort Add center except the problems are on strips that students draw out of a bag or wherever. I printed mine on different colored paper so each group had a different color. You don't need to do that though, I'm a little crazy with my differentiation. I put the easy problems in the yellow bag, medium problems in the blue bag, etc.

Adding 3 numbers math centers and ideas to practice addition problems with 3 addends

Another great strategy for teaching children to add 3 numbers is number lines. Again, they should be number line rockstars from the other units so this should come easy to them. If you haven't used number lines to teach addition and subtraction before this, definitely start with just simple addition (2+3) and practice how to use a number line before you attempt this strategy with 3 numbers.

Adding 3 numbers strategies ideas!! Number lines and more!

Have students start at the first number (here it is 5). For some reason, it helps me to draw a little dot at the starting place. Then, count on however many the second number is by hopping on the number line. Again, I draw a little dot at the first rest stop for some reason. Then, they count on however many the third number is by hopping to get their answer. I know you probably didn't need a lesson on how to use a number line but I just can't turn off the teacher voice (does anyone else have that problem??) sometimes. :)

Worksheets should be differentiated to meet the needs of each student. It's a great strategy but you don't want to overwhelm your low kiddos with too many problems or bore your high kiddos with not enough. I also think it's important for the orientation of the problems to change (vertical vs. horizon) so they see the problems in different ways.

I feel like number lines make adding so much easier for the majority of students and the more they practice it, the better they become at using them. I also recommend encouraging them (when they're ready) to make their own number lines on their papers if there isn't one. It's simple to do - they just need to draw a line with some tallies along it, write the starting number on the first one and the numbers that come after, and then use it. I think every little mathematician should be able to make their own. It'll really come in handy during testing!

Speaking of practice, this is a math station favorite. Anything where we get to use dry erase markers, right??

Students take a number line card and solve the problem by using their dry erase marker on the number line at the top. Then, they write the answer in the box. They look at the letter in the bottom left corner and match it to the one on their recording sheet to write the answer in. Simple but fun. To differentiate, simply give them the recording sheet with 12 problems or the one with 8. I also made a slightly harder set of A-L cards with different border colors for the higher kids.

Adding 3 numbers math centers and activities to practice addition problems with 3 addends
Yay for number lines!

Another strategy that can be really helpful for students is to use knowledge they already have to solve the problems quicker. The "Find a Double" strategy is helpful because, if they know their doubles, they really only have to add 2 numbers. For example, if the problem is 3+3+8 and they instantly know 3+3=6 because it is a doubles fact then they only have to do 6+8 to solve the problem.

Find a double to add 3 numbers and other great mental math strategies 

Similarly, they can use the "Make a 10" strategy to solve the problems which is even quicker if they know their tens facts (10+1, 10+2, 10+3, etc.). I think it's best to teach a variety of strategies and hopefully one or two will stick! I know that when I was in school, and even today, I use the make a 10 strategy to add numbers all. the. time. It's the one that works best for me so I love it and use it often but different students may prefer different strategies. As long as it works!

Make a 10 to add 3 numbers and a lot of other great strategies for adding 3 numbers on this post

For this strategy, they simply find the 2 numbers that make a 10 and then add the remaining number. If your students are not yet fluent in which numbers make a 10, I recommend practicing that a lot because it will help them so much in so many different math skills for the rest of their lives. Or maybe I'm just biased because it's the strategy that I use. Go back to Chapter 3.3 in Unit 3 to review making 10 for students who still need help with it. 

I hope those strategies can be helpful for your students!

I'm sure you're sick of me saying it but I think math should be FUN. Because it is. Really though. Did you just click out? If you're still here reading (thank you), I will tell you one of my secret weapons - CUTTING AND PASTING ACTIVITIES. 

Best. Invention. Ever.

Kids love them. Yay! they say. We get to glue! they proclaim. You're the best teacher ever! they cry. (Okay, did I go too far?)

They think they're doing art so they're loving it and are totally engaged when, let's get real, they're really just doing math problems. Teacher trickery at its best. But it's a win-win for both parties!

Here are some of the 32 cut and paste activities included. Yes, 32. I have a cut and paste addiction.



There's just something wonderful about cut and pastes besides students enjoying it. I've said this before but I think students are more careful with their math when there is glue involved because they don't want to glue down a wrong answer. So they actually check their answers first and think harder about it so they do it right.. because they're creating a piece of art in their minds and want it to be nice.

Another thing students love is DICE. If the center has dice, the center is king.

I don't know why kids love dice so much but I'll take it!

Adding 3 numbers activities and math centers that make adding 3 addends so fun

This is a super simple center - they just roll 3 dice and add them up! I love that this center is reusable.. you can use it in your tubs for weeks to keep practicing for as long as the students need it (and for as long as you don't want to have to come up with a new center - score!) because the numbers are different every time. And it's dice (oooh ahhh) so they'll be okay with doing it multiple times. 

Okay, now for the hard stuff. Word Problems!

Not going to lie, I don't really like word problems. They hardly ever have kid friendly wording and sometimes are (annoyingly) purposely confusing.. right?? So I wanted to make sure these had first grade friendly wording - decodable words or at least words they know and simple sight words. I don't think reading should get in the way of showing what you know in math.

Adding 3 numbers word problems that kids can actually do! Lots of fun activities to teach how to add 3 numbers

 For word problems, you may have students who need to use manipulatives to figure them out. They can be really tough for some kids so it's good to provide support. You could give them the ten frame mat if they need, scratch paper to draw the problem, a personal number line to use, or anything that you think might help them.

I wanted students to be able to read/understand the problem, write or at least recognize the number sentence for it, and also be able to match the picture representation to the problem so I created more word problem match up cards. You may recognize this style center from my adding to 10 unit, adding to 20 unit, subtracting within 10 unit, and subtracting within 20 unit... yeah, I use these a lot :) But they are so helpful! Students match the problem to its number sentence and visual representation and then solve. It's a good way to see the problem in a multitude of ways. You can mix and match these with the ones from other units to make great review centers later in the year! Just make sure you have one card for each letter! I made the format exactly the same so they could be mix and matched.

Adding 3 numbers word problems that kids can actually do! Lots of fun activities to teach how to add 3 numbers

And now for the really challenging stuff... missing addends with 3 addends! Dun dun dunnnnn...

This concept can be tough!! I mean, really tough. But they can do it!

If the problem is 8+2+__=15...
*They can draw 15 circles since that is the total sum then cross out 8 of them, then cross out 2 of them. The leftover circles is their answer.
*They can add the 2 numbers they do know together and then solve it like a normal missing addend problem like they did in Unit 7. For example, they'd add 8+2 to get 10 then solve it as if it were 10+__=15.
*They can use manipulatives and a twenty frame (2 ten frames) to solve by putting 8 red cubes in the frame, 2 blue cubes in the frame, then fill the rest of the frame with green cubes until their frame has 15 cubes in it.
*Do you have any other ways?? I'd love to hear them in the comments! It's a difficult skill and I'm always open to learning new ways!

If you follow me on Instagram, you've probably seen this center but it was a hit so I want to share it anyway!

Adding 3 numbers super fun math center for missing addends when there are 3 addends!

Students take the popcorn problem cards and figure out what the missing number (piece of popcorn) is. They put the card under that bag of popcorn. So, if the problem is 5+2+__=10, the missing addend is 3 and they put it under the popcorn bag labeled 3. It made a hard skill a lot of fun! I recommend popping a little popcorn while they work on it and you will have 2 dozen little best friends.

Love this center to practice missing addends when there are 3 addends (lots of adding 3 numbers ideas on this post!)
Who doesn't love popcorn?? There are 2 sets of this center so they can do the center twice with all different problems and numbers.

As if this post isn't long enough, I just want to share one more math station (this pack I've been using all these examples from has 12) called Add It Up! It's great for practice or review. Students simply take a card, solve it, and write it next to the corresponding number on their recording sheet. It's differentiated by color. The easier problems are in pink and are numbers 1-8 for your low kids. Give your on level kids both the pink and blue cards (1-16) and the middle recording sheet. Give your above level kids all 3 sets of cards - pink, blue, and green (1-24) - and the recording sheet on the right.

Here's what it might look like for your on level kids...

Adding 3 numbers math centers and activities that are so much fun for adding 3 numbers

Here's what it might look like for your advanced level kids...

I also made 3 different colored level sets (pink, blue, green) with cards that are all the "Make a 10" strategy as well as 3 sets for the "Find a Double" strategy for even more practice with those skills. For example, all of the "Make a 10" cards have 2 numbers they can put together to make 10 for easier adding on them.

And then, of course, THE TEST. 3 versions as usual. Nothing fancy. :)

Adding 3 numbers test - these are great math assessments on this page

I hope this post helped you feel ready to tackle on adding 3 numbers or at least helped you pick up a few tricks! If you want all the goodies shown in this post, they're ALL included in my First Grade Math Unit 12 pack. This pack has all of the pages you see above and a lot more! There are 73 differentiated worksheets, 12 math stations, 32 cut and paste activities, and more!

Click {HERE} to check out Unit 12 and all these activities!

Click {HERE} to check out all of my other math units!
So far I have Units 1-9 and 12 completed. A lot more are on the way!

For blog posts about other math units of mine, check out:
Telling Time
Place Value
Fact Fluency
Number Sense
Making a 10 to Add
Composing Shapes
Graphing and Data Analysis

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Also - don't forget to join Miss Giraffe's Class so you never miss out on fun ideas and exclusive free stuff from me only for subscribers!


  1. Omg I am in love! Your work is always amazing but I think you've outdone yourself this time. I absolutely love your differentiation and how your word problems actually look fun!! Never thought I'd see the day. Ok enough fan girling over your pack now.
    Sheri :)

    1. Aw thank you so much, Sheri, for your super sweet comment! It made my day!

  2. I am also obsessed with differentiation! Your ideas are amazing! I am definitely a new follower!

    1. Yay for differentiation lovers! :) Thank you so much for taking the time to leave a kind comment!

  3. I love this! Do you have any packs that would apply for Kinder?

    1. Hi Barbara! I think that Units 1 and 2 would definitely be great for kinder- they're all about number sense (recognizing and writing numbers, counting, number bonds, part part whole, ten frames, twenty frames, 1 more/1 less, etc.) so I definitely recommend those. It's heavily differentiated so you can pull the ones that are appropriate for your students :) I also think Unit 3 (Addition to 10), Unit 9 (place value), and Unit 17 (geometry) would be great for kinder. Hope that helps!

  4. Wow! I love your ideas for math centers!!! Do you have a bundle or pack that just has your math centers? If so, I would totally purchase it! :) Thanks!

    1. Thanks so much, Julie! No, all of the centers are only in their units. They go along with all the other worksheets and activities so I keep them all together :)

  5. Using the tens frames to add three numbers is great. This is the first time I have seen this done on a worksheet. What a great resource! I will be able to use this for the students that have mastered the skill of adding two numbers.Thanks!