Mental Computation | AC9M3A02 Worksheets & Videos

🌟 Overview

This page provides engaging worksheets, hands-on activities, and video lessons to help students explore efficient mental strategies using number facts, patterns, and relationships. Students will extend their knowledge of addition and subtraction facts to develop faster and more flexible ways of solving problems without relying on formal written methods or calculators.

Students will build confidence in mental computation, number sense, and strategic thinking by recognising patterns in numbers, using known facts, and applying them to larger numbers.

📚 Lessons in This Unit

Includes engaging videos and worksheets for. Please click on the link to access the worksheets and videos for each subtopic:

🚀 Learning Path (Recommended Order)

Step	🔗 Lesson	💡 What You Learn
1️⃣	🔢 Number Bonds and Partitioning – All ways to split a number	– Understand what partitioning numbers means and learn how number bonds work – Find all possible ways to split a number
2️⃣	✏️Subtraction Using Addition Facts (Fact Families Explained)	-Use addition facts to solve subtraction problems quickly and efficiently (fact families)
3️⃣	🧩 Extending Addition and Subtraction to Larger Numbers	– Use known number facts to solve larger, unfamiliar calculations efficiently

📚 Curriculum Reference

This topic and its accompanying materials are aligned with the Australian Curriculum: Mathematics (Version 9.0).

Code: AC9M3A02

Students learn to:

🧠 Strengthen mental computation without a calculator
➕ Extend and apply addition and subtraction facts to 20
⚡ Develop efficient mental strategies for larger number calculations
🔢 Use known number facts to solve unfamiliar problems
🔍 Recognise and apply number relationships and patterns

🔗 Related Learning Areas

These topics work well alongside AC9M3N04:

📝 Helpful Tips

These activities are designed to strengthen mental computation skills:

🔍 Use known facts first – Build from what students already know (e.g. 6 + 7 helps with 16 + 7)
🔁 Look for patterns – Numbers often behave in predictable ways
🧠 Encourage mental strategies over written methods – Focus on thinking, not setting out
➕ Use partitioning – Break numbers into friendly parts to make solving easier
🔄 Connect addition and subtraction – Use one to help solve the other
💬 Explain thinking – Students should describe their strategy, not just the answer
⚡ Encourage efficiency – Ask: “Is there a faster way to solve this?”