# 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.

### 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

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.

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

• Variation 1: Change the questions examined by students

Category:

• Teaching and learning