{"id":3949,"date":"2015-08-16T10:09:08","date_gmt":"2015-08-16T18:09:08","guid":{"rendered":"http:\/\/www.familymathnight.com\/blog\/?p=3949"},"modified":"2015-08-16T10:17:14","modified_gmt":"2015-08-16T18:17:14","slug":"subitizing-number-sense-in-k-2","status":"publish","type":"post","link":"https:\/\/www.familymathnight.com\/blog\/?p=3949","title":{"rendered":"Subitizing: Developing Number Sense in K-2"},"content":{"rendered":"

I recently had a conversation with a friend about different ways to get her second graders to learn their addition and subtraction facts. \u00a0She was looking for alternatives to flashcards. \u00a0So I shared with her something I do with K-2 students called subitizing. \u00a0Subitizing is being able to quickly recognize the number of objects in a small set without needing to count any of the objects. \u00a0Think about rolling a die. \u00a0When that die settles, a quick glance tells you exactly what number you rolled. There’s no counting of pips involved.<\/p>\n

But that isn’t the case for our younger students. \u00a0Developmentally they still need to count those pips. \u00a0Over time they’ll begin to internalize the patterns and solidify concepts like conservation, cardinality, and part-part-whole relationships (composing and decomposing numbers) \u00a0– each one so important to building number sense. \u00a0My favorite part, though, is when the patterns become automatic and students begin to use the strategy of counting on. \u00a0This strategy will help them when they begin to learn their addition and subtraction facts which brings me back to my friend.<\/p>\n

A super fun way to help second graders solidify their facts is by using dominoes and the doc camera (or overhead projector). \u00a0Have your students get out their individual white boards and markers. \u00a0Tell them you’re going to flash a domino on the screen and their job is to figure out how many total pips they see then write the number on their board. \u00a0Start with a super easy domino – maybe one pip on one side and two pips on the other. \u00a0Flash the domino on the screen for two seconds. \u00a0Give students a moment to write the total on their boards then have them hold up their boards so you can quickly see who got it.* \u00a0Try another one. \u00a0As students get familiar with the game, flash the domino for one second only.<\/p>\n

See what’s happening? \u00a0They’re subitizing! \u00a0As you flash the domino, their brain is quickly recognizing the pip patterns, turning those patterns into quantities and combining them together! \u00a0Love it!<\/p>\n

Below is a photo of first graders I was working with when we played this “game”. They absolutely loved it!<\/p>\n

\"subitizing\"<\/a><\/p>\n

As a variation, you can have students add ‘1’ to the total number of pips flashed. \u00a0So if you flash a domino with 5 total pips, they record ‘6’ since 5 + 1 = 6. \u00a0At a little higher level, students\u00a0find the difference between the two sides. \u00a0Now they’re practicing subtraction. \u00a0For example, if there are 6 pips on one side and 2 pips on the other, they would record ‘4’ on their boards since 6 – 2 = 4.<\/p>\n

If you’re working with younger students start by flashing one die. \u00a0As you flash the die, students will learn to quickly recognize and connect the pip patterns to the quantity. \u00a0Again have the students record the number on their white boards. \u00a0Provide students with a counting strip like the one below which we include in our Nifty Numbers<\/a>\u00a0kit for those students who need the support.<\/p>\n

\"counting<\/a><\/p>\n

The ability to subitize is so foundational to success in mathematics that we need to provide our students with many ways to practice this skill. \u00a0In addition to dice and dominoes on the doc camera, dot-pattern cards and 10-frames work, as well. \u00a0You can see some examples in the photo below. \u00a0Notice how some of the dots do not make familiar patterns. \u00a0Having different arrangements for the same number will help students learn that numbers can be composed and decomposed in a variety of ways.<\/p>\n

\"subitizing<\/a><\/p>\n

Notice also how some dot cards can be made up of two colors. \u00a0In the beginning, this can help students see those different number combinations more easily. \u00a0To increase the difficulty level when using 10-frames, use two 10-frames at the same time.<\/p>\n

If you’d like additional tips on using subitizing activities in your classroom, here is a short video I put together:<\/p>\n