CBSE · Class 7 · Mathematics · Chapter 4
Expressions using Letter-Numbers
Use letters to represent changing or unknown numbers and express mathematical patterns and relationships.
Start chapterLessons in this chapter
- 1The Notion of Letter-NumbersUse letters to describe number relationships that remain useful when the numbers change.
- 2Writing Expressions for Everyday RelationshipsTurn costs, lengths, and everyday instructions into expressions with clearly defined letters.
- 3Revisiting Arithmetic Expressions and Evaluating Algebraic ExpressionsRead signed terms correctly and substitute numbers without losing operation order.
- 4Simplification of Algebraic ExpressionsSee why like terms can be collected and why different-looking expressions can have the same value.
- 5Adding and Subtracting Algebraic ExpressionsCombine whole expressions carefully, especially when a minus sign applies to a bracket.
- 6Equivalent Expressions and Correcting MistakesExplain when expressions agree for every allowed value and locate the steps that cause algebra errors.
- 7Pick Patterns and Reveal Relationships — Formula DetectiveDiscover number-machine rules and build expressions by tracking what each quantity contributes.
- 8Algebraic Expressions to Describe PatternsUse occurrence numbers, cycle remainders, and grid coordinates to predict distant positions.
- 9Patterns in a CalendarUse calendar offsets to explain why diagonal and cross-shaped sums follow general rules.
- 10Matchstick Patterns and Growing FiguresDerive growth formulas by counting new contributions, shared sides, squares, and cut points.
- 11Chapter Summary and PracticeConnect the whole chapter, explain the rules, and apply expressions to mixed situations and patterns.