# Introduction to Algebra

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1) Variables 2) Constant 3) Algebraic expression . This is pre-algebra.

Introduction to Algebra :

Let us fill up the empty gaps.

1) (----) + 3 = 7

2) 3 + ( ----) = 8

3) 8 + 3 = ( ----)

In the first blank you will write 4 , in 2nd you will write 5 and in the 3rd you will write 11. The (---) stands for an unknown number.

Now let us write these problems a little differently.

1) Cost of a pen + $ 3 is equal to $7.

2) After paying the cost of book, Sam is left with $3 from his pocket money of $8.

3) Jill had 8 toffees and her brother gave her 3 more.How many toffees does Jill have now?

In all these cases, we have to find answers, which are not known. They are referred to as

**unknowns**

The mathematics which involves unknowns are called Algebra.

So, in this section I am giving you the Introduction to Algebra.

Literal numbers are generally referred to as

**variables**as there values vary and are not fixed

Example:5 more than a number.

Solution:Here,we do not know the number, so it becomes a variable.

The quantities with fixed numerical values are called

**constants**

Example:5,8,10 etc. are constants.

5 more than a number(a) can be written in mathematical form as "a+5" This is an

**algebraic expression**

1) | If two values are equal, we use the "equals" sign | Equal to | = | Example: 2+2=4 |

2) | If two values are definitely not equal, we use the "not equal to" sign | Not equal | ≠ | Example : 2+2 ≠ 9 |

3) | More than | Addition | + | Example: 7 more than x = x+7 |

4) | Less than | Subtraction | - | Example : 5 less than x = x-5 |

5) | Decrease | Subtraction | - | Example : x is decreased by 2= x-2 |

6) | Increase | Addition | + | Example : x is increased by 3=x+3 |

7) | Twice of a number(a) | Two times | x | Example : 2 times a = 2a |

8) | Thrice of a number (a) | Three times | x | Example : 3 times a=3a |

9) | Double of a number (b) | Two times | x | Example : Double the number b = 2b |

10) | One half or Half of a number(b) | Division | Divide with 2 | Example : One half of b= ½ b = b/2 |

11) | One third of a number (x) | Division | Divide with 3 | Example : One third of x = ⅓ b= b/3 |

**Introduction to Algebra**

• Addition of Literals

• Subtraction of Literals

• Multiplication of Literals

• Division of Literals

• Constants and Variables

• Coefficient

• Addition of Literals

• Subtraction of Literals

• Multiplication of Literals

• Division of Literals

• Constants and Variables

• Coefficient

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