describes mathematical situations using everyday language, actions, materials and informal recordings
uses objects, actions, technology and/or trial and error to explore mathematical problems
uses concrete materials and/or pictorial representations to support conclusions
combines, separates and compares collections of objects, describes using everyday language, and records using informal methods
- Represent practical situations to model addition and sharing (ACMNA004)
- combine two or more groups of objects to model addition
- model subtraction by separating and taking away part of a group of objects
- use concrete materials or fingers to model and solve simple addition and subtraction problems
- compare two groups of objects to determine 'how many more'
- use visual representations of numbers to assist with addition and subtraction, eg ten frames
create and recognise combinations for numbers to at least 10, eg 'How many more make 10?'
describe the action of combining, separating and comparing using everyday language,
eg makes, joins, combines with, and, get, take away, how many more, all together
- explain or demonstrate how an answer was obtained (Communicating, Reasoning)
- apply strategies that have been demonstrated by other students (Problem Solving)
- investigate different methods of adding and subtracting used in various cultures, eg Aboriginal and Torres Strait Islander methods involving spatial patterns and reasoning, Asian counting tools such as the abacus (Communicating, Problem Solving)
- count forwards by ones to add and backwards by ones to subtract
- record addition and subtraction informally using drawings, words and numerals
Addition and subtraction should move from counting and combining perceptual objects, to using numbers as replacements for completed counts with mental strategies, to recordings that support mental strategies (such as jump, split, partitioning and compensation).
Subtraction typically covers two different situations: 'taking away' from a group, and 'comparing' two groups (ie finding 'how many more'). Students should be confident with taking away from a group before being introduced to comparing two groups. They should be able to compare groups of objects by using one-to-one correspondence before being asked to find out how many more or how many less there are in a group.
In Early Stage 1, addition and subtraction problems should be related to real-life experiences that involve the manipulation of objects.
Modelling, drawing and writing mathematical problems should be encouraged in Early Stage 1. However, formal writing of number sentences, including the use of the symbols +, − and =, is introduced in Stage 1.
Addition and subtraction should be taught in conjunction with each other as the foundation for conceptual understanding of their inverse relationship.
Students should be able to communicate using the following language: count forwards, combines with, joins, count backwards, take away, how many more, all together, makes.
Some students may need assistance when two tenses are used in the one problem, eg 'I had six beans and took away four. How many do I have?'
The word 'difference' has a specific meaning in this context, referring to the numeric value of the group. In everyday language, it can refer to any attribute.