Theory:

Till now we have studied about numbers and shapes.
 
We have learned about operations on numbers such as addition, subtraction, multiplication and division. The branch of mathematics that deals with numbers is called arithmetic.
 
Also, we learned about two dimensional, three-dimensional shapes with its properties. The branch of mathematics that deals with shapes is called geometry.
Let us begin with another branch of mathematics called algebra.
 
Branch algebra is an extension of arithmetic.
 
In this, we are going to learn to use the letters (in some places instead of numbers).
 
With the help of letters, we will write formulas.
 
Here we can talk about any numbers, not just a single number.
 
Thus, the branch of mathematics that deals with variables is called algebra.
The branch of algebra will be interesting when coming across the following types of problems:
  1. Calculating the length to fence a garden.
  2. Determining the number of items purchased when the total cost is known.
  3. Finding time taken to travel when distance and speed are known.
  4. Predicting the missing numbers in a sequence.