Class 7 Maths - BIHAR
Expressions using Letter-Numbers
The chapter 'Expressions using Letter-Numbers' introduces Bihar Board Class 7 students to the exciting world of algebra, where letters are used to represent unknown numbers. Students learn to form algebraic expressions using numbers, letters, and operations like addition, subtraction, multiplication, and division. This chapter forms the foundational building block for solving equations in higher classes. Mastering this topic is crucial for scoring well in your Bihar Board examinations, as it tests your logical thinking, ability to translate word problems into mathematical statements, and skills in simplifying algebraic terms.
Start Learning FreeKey Concepts
Variable
A letter (like x, y, or a) used to represent an unknown quantity that can change or vary.
Constant
A fixed numerical value that does not change, such as 5, -7, or 3/4.
Algebraic Expression
A combination of constants and variables connected by mathematical operations like +, -, ×, and ÷.
Term
Parts of an algebraic expression separated by addition (+) or subtraction (-) signs.
Coefficient
The numerical factor attached to a variable in a term, such as 5 in the term 5x.
Important Formulas
Board Exam Info
In the Bihar Board Class 7 mathematics examinations, this chapter typically carries around 6 to 10 marks. Common question types include translating statements into algebraic expressions, identifying terms and coefficients, evaluating expressions by substituting values, and solving simple word problems using letter-numbers.
Frequently Asked Questions
What is the difference between a variable and a constant?
A constant has a fixed value (like 5), whereas a variable uses a letter (like x) whose value can change depending on the problem.
How do we write '5 more than x' as an expression?
It is written as x + 5 because 'more than' means addition.
What is the coefficient in the term -7xy?
The numerical coefficient is -7, which is the number multiplied by the variables.
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