Year level: 4

Strand: Number / Algebra

Lesson length: 60 mins

In the final of these three lessons, students use efficient strategies when performing calculations involving money. They are guided to use the 4-step problem solving method to support unpacking the problem, generating a plan to solve it, and checking their ability to work mathematically.

### Achievement standard

Students use their proficiency with addition and multiplication facts to add and subtract, multiply and divide numbers efficiently.

### Content descriptions

Students develop efficient strategies and use appropriate digital tools for solving problems involving addition and subtraction, and multiplication and division where there is no remainder. AC9M4N06

Students recall and demonstrate proficiency with multiplication facts up to 10 x 10 and related division facts; extend and apply facts to develop efficient mental strategies for computation with larger numbers without a calculator. AC9M4A02

### General capabilities

Numeracy:

Critical and Creative Thinking:

• Interpret concepts and problems Inquiring Level 3
• Identify, Process and Evaluate information Level 3

The following suggestions are recommended for formative assessment for this lesson.

• Keep a record of their problem-solving strategies.
• Have students keep a portfolio of problem-solving activities to show growth and to document learning.

It is expected that students have:

• familiarity with the concept of pocket money
• estimation approaches to making an estimate
• different strategies to calculate the difference between money values involving dollar and cents
• multiplicative thinking skills to find the total of money amounts over the period of time.

Some students may:

• have challenges reading and understanding the problem – there is choice in the way the money can be distributed if students decide to allocate a different value to the jobs performed (The problem doesn’t state that the jobs are all of equal value.)
• find moving from additive to multiplicative thinking when calculating costs for a four-week period difficult (repeated addition to multiplication)
• find shifting to abstract thinking difficult – estimation is an approximate value, not an exact value
• need to move from inefficient to efficient strategies that are embedded in their learning.