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