Introduction
Our study so far has been with numbers and shapes. We have learnt numbers, operations on numbers and properties of numbers. We applied our knowledge of numbers to various problems in our life. The branch of mathematics in which we studied numbers is
We have also learnt about figures in two and three dimensions and their properties. The branch of mathematics in which we studied shapes is
Now we begin the study of another branch of mathematics. It is called algebra.
The main feature of the new branch which we are going to study is the use of letters.
(1) Use of letters will allow us to write rules and formulas in a general way. By using letters, we can talk about any number and not just a particular number.
(2) Letters may stand for unknown quantities. By learning methods of determining unknowns, we develop powerful tools for solving puzzles and many problems from daily life.
(3) Since letters stand for numbers, operations can be performed on them as on numbers. This leads to the study of algebraic expressions and their properties.
You will find algebra interesting and useful. It is very useful in solving problems. Let's begin with a simple example.
Say, we have a shopping list for stationery:
(a) 5 notebooks
(b) 3 pencils
(c) 1 blue pen
(d) 1 scale (15cm)
(e) 2 erasers.
We have Rs. 150 with us to buy all the required items. How much do we need to pay the shopkeeper? Since, the cost of all the items will be different, how to calculate the total cost? This is where algebra comes into play.
Mathematical Expressions gain meaning (in real-life) with the help of algebra.