AC9M4N01
Official content description
recognise and extend the application of place value to tenths and hundredths and use the conventions of decimal notation to name and represent decimals
What AC9M4N01 actually looks like when you teach it
Decimals are best introduced as an extension of what they already own, not as a new topic. The hundred square they used for place value becomes the whole; one column is a tenth; one small square is a hundredth. MAB works the same way if you rename the flat as one. Say the numbers properly from the start — "three point one four", not "three point fourteen" — because the second reading is the source of most later errors. Connecting decimals to the fractions work from earlier in the year is worth an explicit lesson of its own.
What the class will get wrong — and what to do about it
The error
Ordering decimals by digit count, so 0.45 is judged larger than 0.7 because 45 is larger than 7 — the whole-number rule that longer means bigger, applied where it doesn't hold.
How to confront it
Shade both on hundred squares and put them side by side. Then order a deliberately mixed set — 0.7, 0.45, 0.5, 0.09 — on a number line from 0 to 1, where position settles every argument.
Ready to put on the board
We are learning to name, write and compare decimals to hundredths.
- I can read a decimal aloud correctly.
- I can show a decimal on a hundred square.
- I can order decimals and explain how I decided.
Shade and order
- Give each pair four decimals: 0.7, 0.45, 0.5, 0.09. They shade each on its own hundred square.
- Cut the squares out and physically order them smallest to largest.
- Peg them onto a 0–1 number line drawn across the board.
- Ask the trap question first: which is bigger, 0.45 or 0.7? Let the shaded squares answer it.
- Record each as a fraction as well — 0.7 is 70 hundredths — to tie it back to fractions.
Free to use in your classroom. Written for AC9M4N01, not adapted from another year level.
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The Year 4 Maths planning scaffold
A one-page planning sheet with the official achievement standard, every content description grouped by strand, and space for your assessment and week-by-week sequence. Print it and plan on paper, or use it as the skeleton for a unit.
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What Year 4 Maths students should achieve
Coverage is judged against the achievement standard — not by ticking every content description. These are the official Year 4 Maths standard sentences this code builds towards:
- They recognise equivalent fractions and make connections between fraction and decimal notations.
- Students order events or the outcomes of chance experiments in terms of likelihood and identify whether events are independent or dependent.
- They use mathematical modelling to solve financial and other practical problems, formulating the problem using number sentences, solving the problem choosing efficient strategies and interpreting results in terms of the situation.
- They find unknown values in numerical equations involving addition and subtraction.
- Students use the properties of odd and even numbers.
- They choose rounding and estimation strategies to determine whether results of calculations are reasonable.
The Number progression either side of AC9M4N01
A class can only meet this descriptor if they were taught the one before it. If yours hasn't, that's where the lesson starts — not here.
Taught before · Year 3
- AC9M3N01recognise, represent and order natural numbers using naming and writing conventions for numerals beyond 10 000
- AC9M3N02recognise and represent unit fractions including 1/2, 1/3, 1/4, 1/5 and 1/10 and their multiples in different ways; combine fractions with the same denominator to complete the whole
- AC9M3N03add and subtract two- and three-digit numbers using place value to partition, rearrange and regroup numbers to assist in calculations without a calculator
Builds towards · Year 5
- AC9M5N01interpret, compare and order numbers with more than 2 decimal places, including numbers greater than one, using place value understanding; represent these on a number line
- AC9M5N010create and use algorithms involving a sequence of steps and decisions and digital tools to experiment with factors, multiples and divisibility; identify, interpret and describe emerging patterns
- AC9M5N02express natural numbers as products of their factors, recognise multiples and determine if one number is divisible by another
Other Year 4 Number codes
- AC9M4N02explain and use the properties of odd and even numbers
- AC9M4N03find equivalent representations of fractions using related denominators and make connections between fractions and decimal notation
- AC9M4N04count by fractions including mixed numerals; locate and represent these fractions as numbers on number lines
- AC9M4N05solve problems involving multiplying or dividing natural numbers by multiples and powers of 10 without a calculator, using the multiplicative relationship between the place value of digits
- AC9M4N06develop efficient strategies and use appropriate digital tools for solving problems involving addition and subtraction, and multiplication and division where there is no remainder
- AC9M4N07choose and use estimation and rounding to check and explain the reasonableness of calculations including the results of financial transactions
- AC9M4N08use mathematical modelling to solve practical problems involving additive and multiplicative situations including financial contexts; formulate the problems using number sentences and choose efficient calculation strategies, using digital tools where appropriate; interpret and communicate solutions in terms of the situation
- AC9M4N09follow and create algorithms involving a sequence of steps and decisions that use addition or multiplication to generate sets of numbers; identify and describe any emerging patterns
Content description and achievement standard © Australian Curriculum, Assessment and Reporting Authority (ACARA), Australian Curriculum Version 9, used under CC BY 4.0. TeachKoala is not affiliated with or endorsed by ACARA.