An Overview of Cbse Class 7 Maths Notes Chapter 10
FAQs on Cbse Class 7 Maths Notes Chapter 10
1. What is a quick summary of how algebraic expressions are formed for Class 7?
An algebraic expression is a combination of constants and variables connected by mathematical operations like addition, subtraction, multiplication, and division. For example, in the expression 5x - 3, 'x' is a variable, '5' and '3' are constants, and they are connected by multiplication and subtraction. A quick revision of this chapter involves understanding how these building blocks create meaningful mathematical statements.
2. What are the key terms to remember in the Algebraic Expressions chapter?
For a quick and effective revision, focus on these key terms:
- Term: A single part of an expression, like 4x or 7.
- Coefficient: The numerical part of a term that is multiplied by the variable, like the '4' in 4x.
- Factor: The numbers or variables that are multiplied to form a term. For instance, in 7xy, the factors are 7, x, and y.
- Like Terms: Terms that have the same algebraic (variable) factors, such as 2xy and -9xy.
- Unlike Terms: Terms with different algebraic factors, like 3a and 4b.
3. How are algebraic expressions classified based on their number of terms?
Understanding the classification is a core concept for revision. Expressions are named based on how many terms they contain:
- Monomial: An expression with only one term (e.g., 7x).
- Binomial: An expression with two unlike terms (e.g., 2a + 3b).
- Trinomial: An expression with three unlike terms (e.g., x + y - 5).
- Polynomial: A general name for an expression with one or more terms with non-negative integer exponents on the variables.
4. How does identifying 'like terms' help in simplifying algebraic expressions?
Identifying like terms is the most crucial step for simplification. You can only add or subtract the coefficients of like terms. For example, in the expression 3x + 5y + 2x, '3x' and '2x' are like terms. You can combine them to get (3+2)x = 5x. The term '5y' is an unlike term and cannot be combined. This concept simplifies a long expression into a shorter, more manageable one.
5. Why is it important to use brackets when subtracting one algebraic expression from another?
Using brackets is essential to avoid common errors during revision and exams. When you subtract an entire expression, you must change the sign of every term inside the bracket. For example, to subtract (a - b) from (2a + 3b), you write it as (2a + 3b) - (a - b). Opening the bracket changes it to 2a + 3b - a + b. Forgetting the bracket might lead you to only subtract 'a' and not '-b', resulting in an incorrect answer.
6. What is the correct method to find the value of an expression if the variable's value is known?
To find the value of an expression, you need to follow a simple two-step method. First, substitute the given numerical value for the variable in the expression. Second, simplify the resulting numerical expression using the correct order of operations (BODMAS/PEMDAS). For instance, to find the value of 4x - 2 for x=3, you substitute to get (4 * 3) - 2, which simplifies to 12 - 2 = 10.
7. How can we use algebraic expressions to represent real-life patterns, like the perimeter of a rectangle?
Algebraic expressions are powerful tools for creating general formulas. For a rectangle with length 'l' and breadth 'b', the perimeter is the sum of all its sides: l + b + l + b. By combining like terms, we get the expression 2l + 2b or 2(l + b). This single expression can now be used to find the perimeter of any rectangle, no matter its size, just by substituting the values of 'l' and 'b'.
8. What is an effective way to structure a quick revision of the entire 'Algebraic Expressions' chapter?
For an effective quick revision of this chapter as per the CBSE 2025-26 syllabus, follow this structure:
1. Quickly recap the definitions of variable, constant, term, and coefficient.
2. Review the difference between like and unlike terms, as this is fundamental for all operations.
3. Practise one example each of adding and subtracting expressions, paying close attention to signs.
4. Solve one problem on substituting a value into an expression to find its result. This systematic approach ensures all core concepts are covered efficiently.

















