Week 3: Subtraction

Big Ideas

This week, we started by looking at numeracy, and how it is different from mathematics. The words numeracy and mathematic are often used interchangeably but they are fundamentally different:



Then, we focused on the concept of subtraction, and the skills and thinking strategies involved. Subtraction is when you know only one part of a total and you have to work out the other part (Jamieson-Proctor, 2021). Subtraction is the inverse of addition, and there are actually three types of subtraction: takeaway, difference or comparison, and missing addend.

Concept, skill or Strategy


When doing subtraction, the three addition strategies can be used in reverse (count on, use doubles, use 10). Count-back for example can be used in subtraction like count-on in addition. This strategy can be introduced using cover up cards

 
(Jamieson-Proctor, 2021)

These cards are what you may use for children who are at the materials learning stage, and you should cover up real materials if the child is still at the concrete/student language stage.

Misconception

Often when one thinks of subtraction, they instantly think ‘takeaway.’ A common misconception is that there is only one type of subtraction called takeaway, however there are actually THREE types:


To address this misconception, it is important when teaching subtraction to use ALL THREE types of subtraction stories. This needs to begin in prep to lay foundations for understanding that the content of subtraction is not ‘takeaway.

ACARA

Subtraction is first seen in the Australian curriculum in year 1 (ACMNA015)

Strand: number and algebra
Sub-strand: number and place value


Scootle

(ABC Education, 2020)

The Scootle resource, ‘Maths Years F–1 with Miss James: Subtraction using a number line,’ is a good way for children at the mathematics language stage to practice the subtraction strategy of count-back. In this video, Miss James teaches children how work out takeaway subtraction problems using a number line. She starts with a warm up with some quick counting activities, and then teaches children how to create their own number line to use in the activities. When using the count-back strategy, children should not be counting back numbers more than 1-3. Therefore, one misconception that could arise from this resource, is that children may think they can use this strategy with any numbers, as some of the problems presented in the video e.g. 9-7, 5-4.

Teaching Resource

(Rycroft, 2021)

This resource comes from a series of addition and subtraction strategies from primary school teacher, Elyse Rycroft. This particular one stood out for me as it intertwines both addition and subtraction. By completing activities like this, it can help children understand how subtraction is the inverse of addition. In the image, there are a combination of mathematics language and materials used. When teaching with a resource like this, the teacher would need to ensure the students had progressed through all four learning stages of the language model, or make adjustments to the activity to match the stage the children were at.

References

ABC Education. (2020). Maths years F–1 with miss James: Subtraction using a number line. https://education.abc.net.au/home#!/media/3528595/maths-years-f-1-with-miss-james-subtraction-using-a-number-line

ACARA. (2021). Mathematics. https://www.australiancurriculum.edu.au/f-10-curriculum/mathematics/

Connor, J. (2011). The early years learning framework professional learning program: Being numerate. https://wudinnakgn.sa.edu.au/wp-content/uploads/2019/08/Being-numerate.pdf

Department of Education, Training and Youth Affairs. (2000). Numeracy, a priority for all: Challenges for Australian schools. Commonwealth of Australia. https://leo.acu.edu.au/pluginfile.php/4397510/mod_book/chapter/317099/numeracy%20priority%20for%20all.pdf?time=1584439319348

Jamieson-Proctor, R. (2021). EDMA241/262. Mathematics Learning and Teaching 1: Week 3 Part 1 (slide 10). Australian Catholic University

Jamieson-Proctor, R. (2021). EDMA241/262. Mathematics Learning and Teaching 1: Week 3 Part 2 (slide 6). Australian Catholic University

Jamieson-Proctor, R. (2021). Week 3 learning activities: additional short demonstration videos. Australian Catholic University. https://leo.acu.edu.au/mod/book/view.php?id=3379993&chapterid=317101

Ritchhart, R. (1999). Uncovering the dimensions of disciplinary understanding in
mathematics. In L. Hetland & S. Veenema (Eds.), The Project Zero Classroom: Views
on Understanding. Cambridge, MA: Harvard Graduate School of Education

Rycroft, E. (2021). Addition and subtraction activities for kids: fundamental methods. https://proudtobeprimary.com/addition-and-subtraction-to-20-activities-for-kids/?utm_source=pinterest&utm_medium=social&utm_campaign=SocialWarfare&epik=dj0yJnU9NkxnMjhlZjhKOWZHWU9kZEJpeURGZjF3eHpWQ3lIRmcmcD0wJm49QTRBbnl2WWF1TnlFN1VoN3hsNG83QSZ0PUFBQUFBR0IxYzU4












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