What Have We Discussed ?

1.Given two numbers, the one with more digits is the greatersmaller number. If the number of digits in two given numbers is the same, the larger number has a 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 . It follows the largest three digit number . Similarly, the smallest five digit number is . It is ten thousand and follows the largest four digit number .

Further, the smallest six digit number is . It is one lakh and follows the largest five digit number . This carries on for higher digit numbers in a similar manner.

4. Use of commasdashes helps in 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 thousandmillion and millionthousand respectively.

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 = metres, 1 metre = centimetres or millimetres etc.