We're seeing spots!

We have begun our new math unit exploring numbers to 20! A major concept we have just started practicing is subitizing. Subitizing is being able to look at a group and know how many there are, without having to count each individual item. In short, subitizing is "instantly seeing how many". 

We subitize when we roll a die. You didn't have to count the dots to know you rolled a five, right?

What better way to practice this new skill of subitizing then to play games!

Subitizing BINGO
 

Snakes & Ladders, but instead of rolling a dice,
the students flip over a subitizing card

Memory with subitizing cards

KaBOOM,
(a version of the game traditionally called "war")

A subitizing game on the SMARTboard

 
Subitizing helps us see patterns, identify relationships between numbers, and understand place value. We were introduced to a tool called a 10-frame, that can also be used for subitizing. 10-frames are two rows of five boxes, and they help us see how numbers relate to five or ten. Here is a 10-frame:

  We made a GIANT 10-frame and filled it with the cutest counters you have ever seen! Can you see how we made the numbers one through ten?

10-frames will be used in an upcoming unit when we tackle addition and subtraction to 10. We can even put two 10-frames together to work with numbers to 20!

Do you like a challenge? We sure do! Play the subitizing game below. Quickly say how many dots are on the 10-frame. Here is a hint we discovered: sometimes the empty boxes in the frame help us know how many frames are actually full. It's fast!