Do you like to play snake & ladder ? I am sure you do. You always try to get a ‘6’ on the cube , so that you get another chance to roll the die , don’t you ? Each number that you get on the die decides your luck in the game. So is the case with many other interesting games . Numbers and working with numbers is the extremely interesting and learning more about them will make you love Maths.

So , let us go on and have some fun learning about different numbers.

**What are natural numbers ?**

All numbers used for counting are called natural numbers . Natural numbers are those that we commonly use in our daily lives . 1,2,3,4….. and the infinite numbers are all natural numbers.

- The smallest natural number is 1.

**What are digits ?**

All the figures : 0,1,2,3,4,5,6,7,8,9 are called digits . Digits are those figures which are used to form different numbers

**Comparison of numbers **

**How do you know which number is greater or lesser than the other ? Here is a trick to know that :**- Suppose you have two different numbers and you want to know which number is greater than the other
**.**You have to do this - Check which number has more number of digits. That number which has more digits will be the greater number . For example : Take two numbers , 3467 and 897 . Out of these , 3467 has 4 digits , and 897 has 3 digits. So , now we know that the greater number is the 4 digit number
- There is one more case . Sometimes , both the numbers will be having equal number of digits. What would you do in that case ? Don’t be confused. This is the trick : The number with the greater digit on the left side will be the greater number. For example : 65 and 85 . In this case , the number on the left side , ie , 8 is larger than 6 , and hence , 85>65.
- Sometimes , both the numbers will have equal number of digits and will be having the same digit on the left side . In that case , check for the number with the greater digit on the right side. The number with the greater digit on the right side will be the larger number. For example: 57 and 53 . In this case , 7>3 , and hence , 57>53.

**Estimation of numbers**

You are in a supermarket and have bought a lot of chocolates , biscuits and chips. You are standing in the queue at the counter for billing everything you purchased. You just want to have some fun and want to calculate the total sum of all your items before you give them to the cashier. How can you do this quickly ? Here is a situation where you can estimate the total sum of all your products and get an idea of how much you will have to pay . It is very easy .

All you need to know is how to **round off numbers** to their nearest 10.

Learn how to do quick and easy calculation and surprise your friends. There are a few rules you need to follow :

- For all numbers that end in 1,2,3 or 4 , round off to the nearest lower number that ends in 0. For example : 71, 72, 73 and 74 can be rounded off to 70.
- For all numbers that end in 5,6,7,8,9, , round off to the nearest larger number that ends in 0. For example : 75,76,77,78,79 can be rounded off to 80.

This way , you can find the approximate total sum of all the items you purchased simply by adding numbers that end in 0,..That is a very easy calculation. Isn’t it?

**Roman Numbers**

These numbers were used in ancient Rome , to represent different values . They use the Latin alphabet to signify values. This is how each number in our system is represented using the Roman numerals

Conventional numbers | Roman numbers |

1 | I |

2 | II |

3 | III |

4 | IV |

5 | V |

6 | VI |

7 | VII |

8 | VIII |

9 | IX |

10 | X |

You must have noticed that most clocks use Roman numerals to represent time .

We also use Roman numerals after people’s names For example : King Lois XVI

**Importance of using brackets **

What if your teacher asks you to do a large number of calculations , with many operations ? Wont you get confused ? This is why we have brackets . Brackets help you to do your calculations very easily and quickly .

For example : What if your teacher gave you the following sum : 6 + 5 * 7 = ? Will you do 6+5 first , or 5*7 first ? In this situation its highly helpful to have brackets at the right place to help you calculate correctly . So , now the correct problem becomes ( 6+5)*7 = ? Now, we can solve it .

6+5 = 11 , and then 11*7 = 77 is the final answer.

Another example : ( 7+4)*(9+4) = 11* 13 = 143

Now , you have good idea of what natural numbers are and also learnt to do fast calculation.

You are good to go now and to further have fun with Mathematics.

**1**.**0 is the only number that can’t be represented as a Roman number.****12 + 3 – 4 + 5 + 67 + 8 + 9 = 100**

Stay tuned with Byju’s to enjoy the process of learning !