Education Technology

• ##### Device
• TI-Nspire™ CX
• TI-Nspire™ CX CAS
• TI-Nspire™ Apps for iPad®
• ##### Software

TI-Nspire™
TI-Nspire™ CAS

ACMNA151

3.9

# Year 7: Mental Mathematics

by Peter Fox

#### Objectives

• ACMNA151 – Apply the associative, commutative and distributive laws to aid mental and written computation.

#### Vocabulary

• Distributive law
• Units
• Tens
• Digit
• Product
• Sum

#### About the Lesson

Starting with a visual representation (rectangle) for the product of two numbers students can step through the problem. The diagram uses colour, labels and numeric representation to link calculation steps. Students complete the calculations on the hand-out sheet and check their answers with a calculator. After completing the visual representation of the distributive law they work with a more symbolic approach and compare these methods with traditional ‘long multiplication’ methods. The objective is for students to develop efficient mental strategies to work with number.