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### Revision Notes — Class 6 Maths

**Chapter 11 – Algebra**

* Algebra is a general form of arithmetic in which numbers are represented by letters that are joined according to arithmetic rules.
* We looked at matchstick patterns for producing letters and other forms. We learned how to express the general relationship between the numbers of matchsticks necessary to repeat a certain shape in writing. The amount of times a particular shape is repeated varies; it can be 1, 2, 3,... It's a variable that's represented by a letter like n.
* A variable's value can change over time; it is not fixed. A square's length can be any number. It's a variable, after all. The number of angles in a triangle, on the other hand, has a fixed value of three. It isn't a parameter.
* To represent a variable, we can use any letter, such as n, l, m, p, x, y, z, and so on.
* A variable allows us to articulate relations. Variables are numbers that do not have a set value. We can perform addition, subtraction, multiplication, and division on them in the same way that we do with fixed integers. We can create equations with variables like **x − 3, x + 3, 2n, 5m, 3p, 2y + 3, 3l − 5**, and so on by using various operations.
* Many common laws in geometry and arithmetic can be expressed in a general form using variables. The rule that the total of two integers remains the same if the order in which they are obtained is reversed, for example, can be written as **a + b = b + a**. The variables a and b can be any number, such as **1, 32, 1000 − 7, −20**, and so on.
* A condition on a variable is referred to as an **equation**. It is expressed by asserting that a variable expression equals a fixed number, such as **x − 3 = 10**.
* An equation has two sides, **LHS** and **RHS**, with the equal (=) sign in the middle.
* Solution of an equation: The value of a variable in an equation that satisfies the equation is known as the solution.
* The trial and error approach is on

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