Monday, July 24, 2017

Subitizing DIY

Do your kids struggle with subitizing numbers? Subi-say what?! I know quite the mouth full huh? Honestly I was not familiar with this term in my early years of teaching. I think this definition pretty much sums (no math pun intended;) ) it up for us! 

Subitizing is the ability to 'see' a small amount of objects and know how many there are without counting. Subitizing is what tells you what number you roll on a six sided dice – most adults no longer have to count the pips after playing board games for a while.

Having the ability to do this at the primary grades really is so important for numeracy. It does transition over as well in the intermediate grades with higher order mathematics. 

According to The National Council of Teachers and Mathematics, one key part of effective subitizing is developing pattern recognition. Moreover, this mathematical skill allows students to gain a grasp of numbers and advance to higher levels of addition. As an activity, the NCTM suggests taking “snapshots”. Taking snapshots means showing an image of a collection of objects to the student for just a second, then asking him or her to take a mental “snapshot” in order to identify how many objects are included in the image. (

Some benefits of subitizing:

*Saves Time-not having to count each individual member of the group

*Precursor for more complex number ideas-Students who can Subitize small groups of numbers are able to develop their counting skills by beginning their counting after the subitized group, or by using subitizing to count forwards or backwards by twos, threes, or even larger groups later when they are exposed to more complex multiplication tables. (Reys, et al., 2012) This type of subitizing falls into the category of conceptual subitizing which occurs with larger number sets, and involves  breaking the group into smaller parts (Clements, 1999). 

*Lends itself to learning addition and subtraction easier- it means that they are better equipped to handle addition and subtraction concepts, as they do not have to count each small group to be added or removed when learning operations with manipulatives (Reys, et al., 2012). 

Also having a strong base in doubles, number combinations, as well as making ten really creates the ability to subitize and group numbers together when in sets higher than 10. 

Having taught first grade the concept of subitizing was essential in our math journey. There are many activities you can do with kids to scaffold and teach them how to subitize. One quick and easy DIY I am listing below! 

We did this activity as a math warm up daily and it took us less than 5 minutes. Gosh, make it a race for them, bettering their time each time. This can be done whole group or small group. You can now get subitizing cards all over TPT,etc, but these little guys are cheap and require no ink! We made these with our math coach (Hey Jackie!) one year and I have been pulling them back out for my tutoring. All you do is flash the plate! 

Prompting some questioning while doing this as well really gives the kids a chance to express their math thinking and also gives you as the teacher a chance to hear if they really understand. 
Some examples of questions you can ask after flashing a plate/card: 
-how did you get that number?
-how do you know?
-what did you see?
-how did you group?

You could also hold up a plate and ask:
-what is one more/less than this number?
-what is ___more/less than this number?
-is this odd or even?

Some responses I have heard from kids might be:
-it is 8 because I see 4 here and 4 here and 4 and 4 make 8
-it is 6 because I grouped 4 and 2
-the number is 9 because I see 4 and 4 and one more make 9
This also lends itself to eventually add three numbers as well because of how they are grouping combinations. 
I have also heard kids say "Well I visualized that dot moved down to make a row of 5 then added the extra dots" *mind blown teacher* right?! When you can get your mathematicians talking and discussing like that it is amazing!!! 

It is also VERY important to point out and let the kids discover there may be more than 1 way to subitize and get to their answer. I often have kids say one of the responses above and another kid say a different way they saw it but still are able to produce the same number as their answer. 
I have also seen firsthand how quickly they get better at recognizing numbers, building that number sense, and utilizing strategies to make the combinations faster (make ten, doubles, etc)

So onto the DIY:
Materials needed: paper plates (we used the small ones and the cheapest ones)
                             sticker dots (two different colors)
Then add the dots in different configurations on the plates! 
Use my plates as an example.

Also, what if you put subitizing configurations in a math station and some extra plates, index cards, scrap paper, sentence strip pieces, etc. and they create their own subitizing cards with dots, paint, bingo dotters?! EEK how fun right?

Some other ways to incorporate subitizing into your daily schedule:
-put subitizing dots on your stations instead of the actual number
-subitize as an entrance ticket in the morning on their way through the door
-display your number line with dots under each number

Kids can subitize things other than dots:
-tally marks

A few minutes a day will make a difference! 

Have a Blessed Day!

"Be Good to People"

1 comment:

  1. Thanks for the detailed explanation! The term in much more clear in my mind now! And this activity is so simple to prep in the classroom!