Subitising / Part-Part-Whole – Step 7

  • Where are they now?

    Recognises multiple collections of 20 without counting (e.g. 3 threes, 1 six and 1 five)

  • Where to next?

    Recognises 1000 of these is 1 of those (recursion of ‘hundreds, tens and ones’ patterns to name larger whole numbers)

  • Purpose

    The skill of subitising, of identifying patterns representing quantities using an internalised model, has been well consolidated at this point. The focus now moves to the recursive struture of large numbers – students learn that it is valid to count and structure units of one thousand in the same way they do with units of one. That is, you can have ones, tens and hundreds of thousands. Strictly speaking, this concepts is probably more closely related to the Place Value aspect of part-part-whole understanding, but it still draws on the ability to visualise a group as a countable unit; an ability students demonstrate when they are able to subitise collections which include a number of grouped tens.

Activities and Assessments (designed to move students from step 7 to step 8)

Double Ten Frame Addition

Focus: Students develop strategies through the use of a visual and concrete model for rapidly adding two single digit numbers to a total of up to 20

How: The game is played with teams of two versing one another (four players in total). Each player in a team spins a spinner and then fills a blank ten frame with a corresponding number of counters. The two members of the team then place their ten frames side by side and move counters off one onto the other in order to make 10. In this way they determine the total of the the two frames. Once they have determined the total, they place a counter of their team colour onto a common game board. The first team to get three numbers in a row (horizontally, vertically or diagonally) wins.

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    Ten Frames

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    Ten Frame Addition boards

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    Ten Frame Addition spinners

Subitising Flash Cards

Focus: Students become proficient at quickly determining (subitising) the total of up to four groups for collections up to 20

How: The teacher or group leader flashes (displays for about 2 seconds) a card from a set to the class or group. The first student to call out the total receives the card. The sucessful student then explains how he/she determined the total. The student with the most cards once the set has been used is the winner.

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    Subitising Cards (groups to 20)

See-Say- Bingo (random groups to 20)

Diagnostic assessment task suitible for indiviual students or small groups

Focus: Developing automaticity in identifying how many objects are in a collection – Identifying the total of a grouped collection (three and four groups) up to a total of 20.

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    See-Say Bingo instructions

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    Bingo Cards

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    Subitising Cards (groups to 20)