Page 9 - Maths Class 06

EXAMPLE 10. Write the smallest three digit number which does not change even if the digits are written
in reverse order.

SOLUTION : We know that at hundred’s place, 1 is the smallest digit. We also know that at ten’s place 0
is the smallest digit. Thus, we must have at one’s place that digit which we have at
hundred’s place. Hence, 101 is the required number.

Large Numbers
All of us are familiar with computers. Talking about computer memory usually means a talk about
kilobytes (1000 bytes), megabytes (1,000,0000 bytes), gigabytes (1,000,000,000 bytes), etc. These
words have become common in our vocabulary but we need to understand the value of these numbers.
In a school, the students of Class VI decided to find out how big one million (1,000,000) is. They planned
to collect 1 million matchsticks. Each matchbox usually contains 50 matchsticks. 10 such boxes are
usually packed as one packet. So a packet of matchboxes contains 500 matchsticks. The students
calculated and found that they needed 2000 such packets to have 1 million matchsticks. 1000 students of
the school decided to bring 2 packets of matchboxes each to make 1 million matchsticks. Imagine the size
of 1 million matchsticks packed in 2000 packets of matchboxes with 500 matchsticks in each! There are
also numbers which are very small. For example, you know the length of 1 metre. In comparison, 1 mm
1 1
= m and 1 mm = km. To live with an understanding of the world around us, we need to
1000 1000 000, ,
learn the meaning and the quantitative values of these big and small numbers.

Introducing 6, 7, and 8-digit Numbers
We know that, 999 + 1 1000= 9999 + 1 10 000= , .

The largest 5-digit number is 99,999. On adding 1 to 99,999, we get the smallest 6-digit number.
99,999 + 1 = 1,00,000.
The new number 1,00,000 which comes just after 99,999 is read as one lakh.

For example, Take a 6-digit number 3,45,678. It is read as three lakh forty-five thousand six hundred
seventy-eight.
The largest 6-digit numbers is 9,99,999. On adding 1 to 9,99,999 we get the smallest 7-digit number.

9,99,999 + 1 = 10,00,000.
The new number 10,00,000 which comes just after 9,99,999 is read as ten lakh.
For example, Take a 7-digit number 34,12,652. It is read as thirty-four lakh twelve thousand six hundred
fifty-two.
The largest 7-digit number is 99,99,999. On adding 1 to 99,99,999, we get

99,99,999 + 1 = 1,00,00,000.
The new number 1,00,00,000 is the smallest 8-digit number which is read as one crore.

An 8-digit number like 5,20,13,275 is read as five crore twenty lakh thirteen thousand two hundred
seventy-five.
Use of Commas

While reading and writing large numbers, it creates confusion as there are many digits in a number. To
avoid making mistakes, we use commas to divide the number into different periods. We can divide a

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