Equality and equations
Read equality as a relationship, find the permitted values that make an equation true, and justify one-step solutions by reversible operations on both sides. Work exactly with negative numbers and fractions, recognize all-solution and no-solution cases, and check the original equation, units and context.
Key knowledge
An equation asserts that two expressions have the same value. A solution is an assignment of values in the stated domain for which the equality holds. Adding or subtracting the same number on both sides preserves equality.
Values and equations
a = b ⇔ a + c = b + c
- a, b, c
- Real numbers
Conditions and scope
- Every expression must be defined at a proposed solution.
- Preserving equality does not justify every transformation as reversible; check whether an operation introduces or removes solutions.
Sources · 6
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
- TIMES · Linear equationsAustralian Mathematical Sciences Institute (AMSI)Teaching resource
- Mastery Professional Development · 2.2 Solving linear equationsNational Centre for Excellence in the Teaching of Mathematics (NCETM)Teaching resource · PDF
- Explanatory Notes to Junior Secondary Mathematics Curriculum (2020) · Learning Unit 8Education Bureau, Hong Kong · Curriculum Development InstituteReference guide · PDF
Evidence and review
Equation, solution and reversible additive transformation.
2026-10-10 · Checked equality properties; no general endorsement of unrestricted cancellation or squaring.
Foundational review
2026-10-10 · Fresh primary-source inspection of the complete compact record, including every statement, equation, quantity and material condition, followed by independent AI editorial review. This check does not certify all linked lessons or every passage of every cited publication.
Sources from other places
Scope or convention differs
Equalities and addition/subtraction preserving their solutions.
The repository requires checking other operations separately for lost or added solutions.
Australian Mathematical Sciences Institute and University of Melbourne
- TIMES · Linear equations AustraliaEnglish
Solving simple equations; Adding and subtracting the same number from both sides
- TIMES · Linear equations
Related articles
Equality and one-step equations ↗Entry details
Permanent link to this entry ↗- Record identity
- equations
- Revision
- reference-core.1
- Published lesson seed
- first-algebra-equality