Negative Numbers in Real Life
Year 8 Mathematics Exploring negative numbers through real-world contexts Temperature and Finance Applications
What Are Negative Numbers?
Numbers less than zero Written with a minus sign (-) Found everywhere in real life Opposite of positive numbers
Temperature and Negative Numbers
Celsius scale uses negative temperatures Below 0°C = freezing point of water Winter temperatures often negative Weather forecasts show negative values
Whole Class Activity: Temperature Detective
Work in pairs to research real temperatures Find the coldest temperature recorded in NZ Compare temperatures from different NZ cities Plot temperatures on a number line
Money and Negative Numbers
Bank account overdrafts Debt represented as negative amounts Credit vs debit transactions Financial statements show negative balances
Positive vs Negative in Finance
{"left":"Money earned from jobs\nDeposits into accounts\nSavings and investments\nGifts received","right":"Money spent on purchases\nBills and expenses\nLoan payments\nBank fees and charges"}
Independent Activity: Budget Tracker
Create a weekly budget for a teenager Include income (pocket money, part-time job) List typical expenses (food, transport, entertainment) Calculate final balance (positive or negative)
Ordering Numbers on a Number Line
Numbers increase from left to right Negative numbers get smaller as they move left -10 is smaller than -5 Zero separates positive and negative numbers
Quick Check: Which is Colder?
A) -8°C or -3°C? B) -15°C or -20°C? C) 2°C or -1°C? Discuss your reasoning with a partner
Summary: Negative Numbers Everywhere
Temperature below freezing point Money owed or spent Depths below sea level Time before an event (countdown) Ordering using number lines helps comparison