Flexible additive strategies - Decimals

This resource has been developed in partnership with the NSW Mathematics Strategy Professional Learning team, Curriculum Early Years and Primary Learners, and Literacy and Numeracy.

Using the resource

This resource is the last section of a four-part resource supporting additive thinking. Use this resource in conjunction with the other resources in this series in order to support a connected network of critical mathematical concepts, skills and understanding.

Supporting tasks

Full instructions on how to use each of these tasks - including materials, related tasks and learning intentions - are included in the resource available for download on this page.

Task 1: Decimals on a number line

Students visualise fractional quantities using an unmarked one-metre strip of paper

  • Variation 1: Students match fractional notation, word cards and images to the number line

Task 2: Making tenths and hundredths

Students partition paper into equal-sized parts to understand tenths and hundredths.

  • Variation 1: Students identify a part of their whole and record the fractions in a range of ways

  • Variation 2: Order the various fractions on a number line, comparing their models and counting forwards and backwards, naming and renaming

  • Variation 3: Make connections to metric units of measurement

  • Variation 4: Make connections to percentages

Task 3: Get your balance: tenths and hundredths

Students use a balance scale and weights to work out different ways of creating one kilogram.

  • Variation 1: Student use an unbalanced scale

Task 4: I’ll race you to zero: decimal place value

Students use mental strategies to subtract decimals using a 12 chart and dice.

  • Variation 1: Students make a number roll by cutting their 12 chart into strips and joining them into one number strip. Students can roll it up when out of use

  • Variation 2: Students use a 1 and 2-tenths chart

Task 5: More than or less than?

Students estimate and determine which of a set of problems are approximately equivalent to 250.

  • Variation 1: Student sort problems into less than and greater than categories

  • Variation 2: Change the target number and problems

Task 6: Roll 5 dice: decimal version

Students work out how many ways one number can be related to another using any operation.

Task 7: What can you say?

Students flexibly rename decimal fractions.

Task 8: How does knowing…?

Students adapt flexible strategies used with whole numbers to add and subtract decimal numbers.

Task 9: Red or black: decimals

Students adapt mental strategies used with whole numbers to add and subtract decimal numbers.

Task 10: Subtraction face-off: thousandths, hundredths and tenths

Students use an Explanation spinner and share the strategies used to work out differences.

Task 11: Number sentence battle

Students build number sentences using dice.

Task 12: Which would you work out in your head? Place value system

Students use mental, written and digital strategies to solve problems.

  • Variation 1: Change the questions examined by students


  • Teaching and learning

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