Inflation and Depreciation

≈ 25 min

0/4 practice checks

Inflation and Depreciation

Inflation multiplies prices by $1+i$ while reducing-balance depreciation multiplies values by $1-i$ . Rates and number of periods must use matching time units. At Grade 10, fluent symbolic work must stay connected to graphs, tables, diagrams and real quantities.

Worked reasoning

Use multiplier $1-0.20=0.80$ .
$12000(0.80)=9600$ .

Key idea

Rates and number of periods must use matching time units.

A phone worth R12 000 depreciates 20% in one year. Find its value.

Which statement best captures the central mathematical idea in Inflation and Depreciation?

Rates and number of periods must use matching time units.

A memorised rule may be used without checking signs, domains, units, graph family or geometric hypotheses.

A memorised formula is valid even when its conditions are not met.

The diagram or notation replaces the need to justify each mathematical step.

When starting a problem about Inflation and Depreciation, which move is most reliable?

Identify the mathematical family, list the given quantities and state the domain or geometric conditions for inflation and depreciation.

Round every value before identifying the mathematical structure.

Choose the longest available formula and substitute immediately.

Assume the desired conclusion and work backwards without checking equivalence.

Which statement is a misconception that must be rejected when working with Inflation and Depreciation?

A memorised rule may be used without checking signs, domains, units, graph family or geometric hypotheses.

Rates and number of periods must use matching time units.

Identify the mathematical family, list the given quantities and state the domain or geometric conditions for inflation and depreciation.

Use substitution, a second representation or a magnitude estimate to verify the result.

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