The purpose of this activity is to support students in recognising that two sets can be compared both additively ("so many more or less") and multiplicatively ("times as many").
Pose similar comparison problems looking for students to make statements about difference and "times as many.”
Ask students to record equations for the comparisons they make, addition and subtraction for differences, multiplication for “times as many” and multiplication for fraction comparisons, such as 1/4 x 20 = 5.
You might find it useful to have students with different levels of mathematical knowledge working together, to allow for peer scaffolding and extension of knowledge.
Example might be:
Next steps
Increase the level of abstraction by covering the materials or using diagrams without visible numbers of cubes (e.g. bars or paper strips).
Ask anticipatory questions like “how many times do you think a 5-stack fits into a 15-stack?”
Extend the difficulty of the comparisons so students apply a full range of their basic multiplication facts.
Encourage the application of students' basic multiplication facts by presenting them with culturally relevant problems (e.g. there are 20 boys and 5 girls in our classroom. How many times larger is the group of boys than the group of girls?), or by asking students to make up similar problems with the use of other relevant materials (e.g. stick figures, animal toys).
Printed from https://meaningfulmaths.nt.edu.au/mmws/nz/resource/comparing-sets-using-addition-and-multiplication at 9:02pm on the 26th February 2024