Modelling Composite Units and Counting by Ones
Modelling Composite Units and Counting by Ones: What is it?
Modelling composite units and counting by ones is an early multiplication/division strategy where the student directly models groups of numbers and counting all by ones.
Overview
In the early stages of multiplicative thinking, students need to directly model problems in order to further develop their understanding. When students are using this strategy they model the composite unit (the number of objects inside one group, as a unit). In this case 5 pieces of gum in each pack. The student will count out the number of objects required in the group and will repeat this process until they have modeled the number of groups required for the problem.
For example, if asked the product of 3 x 5 the student would count out 3 groups of 5.
Finally, they would count all of the objects by ones.
Supporting Students Using Modelling Composite Units
Almost all students will need to use this strategy in early multiplication and division to model their thinking and begin to unitize amounts (that is, to think of 5 pieces of gum is also 1 pack). Encourage students to use manipulatives such as tiles, unifix cubes, coloured counters etc. when solving problems. Students will often model this strategy using drawings also. This strategy is used when students 'know' the number inside each group (quotative division). For example, You have 15 cookies and want to give everyone 3 cookies. How many people will get cookies?
Where to Next?
Once students are efficient with modelling composite units, students should be encouraged to begin to ‘Count Rhythmically’ and move toward ‘Skip Counting’
Using Concrete Tools
When students are exploring the early stages of division, the use of concrete tools is essential. Providing as much hands on opportunity will support students to deepen their divisional understanding.
Looking to learn more? Check out the recorded session!