# What Have We Discussed ?

1.Given two numbers, the **one with more digits** is the **greater leftmost digit.** If this digit also happens to be the same, we look at the next digit and so on.

2. In forming numbers from given digits, we should be careful to see if the conditions under which the numbers are to be formed are satisfied. Thus, to form the **greatest four digit number** from **7, 8, 3, 5** **without repeating a single digit,** we need to use all four digits, the greatest number can have only **8** as the **leftmost digit**.

3. The **smallest four digit number** is **largest three digit number** **smallest five digit number** is **ten thousand** and follows the **largest four digit number**

Further, the **smallest six digit number** is **largest five digit number**

4. Use of **reading and writing large numbers.**

5. In the **Indian system of numeration**, we have commas after 3 digits starting from the right and thereafter every 2 digits. The commas after 3, 5 and 7 digits separate **thousand,** **lakh** and **crore** respectively.

6. In the **International system of numeration**, commas are placed after every 3 digits starting from the right. The **commas** after 3 and 6 digits separate

7. **Large numbers** are needed in many places in daily life. For example, for counting number of students in a school, number of people in a village or town, money paid or received in large transactions (paying and selling), in measuring large distances say between various cities in a country or in the world and so on.

8. **Remember** **kilo** shows **1000 times larger**, **Centi** shows **100 times smaller** and **milli** shows **1000 times smaller**. Thus, 1 kilometre =

## Indian place value chart

Crores | Lakhs | Thousands | Ones | |||||
---|---|---|---|---|---|---|---|---|

Ten Crore | Crore | Ten Lakh | Lakh | Ten Thousand | Thousand | Hundred | Tens | Ones |

10,00,00,000 | 1,00,00,000 | 10,00,000 | 1,00,000 | 10,000 | 1,000 | 100 | 10 | 1 |

## International place value chart

Millions | Thousands | Ones | ||||||
---|---|---|---|---|---|---|---|---|

Hundred Million | Ten Million | Million | Hundred Thousand | Ten Thousand | Thousand | Hundred | Tens | Ones |

100,000,000 | 10,000,000 | 1,000,000 | 100,000 | 10,000 | 1,000 | 100 | 10 | 1 |

## Units conversion table

Mnemonic | Prefix | Relation with basic unit | Short Form | Scale |
---|---|---|---|---|

King | Kilo | 1 Kilo=1000 units | km =kilometer kL=kiloliter kg=kilogram | 10x10x10 LARGER than a unit |

Henry | Hecto | 1 hecto=100 units | hm=hectometer hL=hectoliter hg=hectogram | 10x10x LARGER than a unit |

Died | Deca | 1 deca=10 units | dam=decameter daL=decaliter dag=decagram | 10x LARGER than a unit |

By | Basic Unit | 1 unit | m=meter L=liter g=gram | Meter (length) Liter (liquid volume) Gram (mass/weight) |

Drinking | Deci | 10 deci = 1 unit | dm=decimeter dL=deciliter dg=decigram | 10x SMALLER than a unit |

Chocolate | Centi | 100 centi = 1 unit | cm=centimeter cL=centiliter cg=centigram | 10x10x SMALLER than a unit |

Milk | Milli | 1000 milli = 1 unit | mm=millimeter mL=milliliter mg=milligram | 10x10x10x SMALLER than a unit |