AC9M2N04 Year 2 Mathematics

This Content Descriptor from Year 2 Mathematics provides the specific knowledge and skills students should learn. Use it to plan lessons, create learning sequences, and design assessments that align with the Australian Curriculum v9.

add and subtract one- and two-digit numbers, representing problems using number sentences, and solve using part-part-whole reasoning and a variety of calculation strategies

Elaborations

• 1 using the associative property of addition to assist with mental calculation by partitioning, rearranging and regrouping numbers using number knowledge, near doubles and bridging to \(10\) strategies; for example, calculating \(7 + 8\) using \(7 + (7 + 1) = (7 + 7) + 1\) , the associative property and near doubles; calculating \(7 + 8\) using the associative property and bridging to \(10\) , \(7 + (3 + 5) = (7 + 3) + 5\)
• 2 using strategies such as doubles, near doubles, part-part-whole knowledge to \(10\), bridging tens and partitioning to mentally solve problems involving two-digit numbers; for example, calculating \(56 + 37\) by thinking \(5\) tens and \(3\) tens is \(8\) tens, \(6 + 7 = 6 + 4 + 3\) is one \(10\) and \(3\), and so the result is \(9\) tens and \(3, 93\)
• 3 representing addition and subtraction problems using a bar model and writing a number sentence, explaining how each number in the sentence is connected to the situation
• 4 using mental strategies and informal written jottings to help keep track of the numbers when solving addition and subtraction problems involving two-digit numbers and recognising that zero added to a number leaves the number unchanged; for example, in calculating \(34 + 20 = 54, 3\) tens add \(2\) tens is \(5\) tens which is \(50\), and \(4\) ones add zero ones is \(4\) ones which is \(4\), so the result is \(50 + 4 = 54\)
• 5 using a physical or mental number line or hundreds chart to solve addition or subtraction problems, by moving along or up and down in tens and ones; for example, “I was given a \(\$100\) gift card for my birthday and spent \(\$38\) on a pair of shoes and \(\$15\) on a t-shirt. How much money do I have left on the card?”
• 6 using First Nations Australians’ stories and dances to understand the balance and connection between addition and subtraction, representing relationships as number sentences

Related Achievement Standards