Page 12 - ICSE Math 4

Example 1: Group 398104 by pu ng commas according Top Tip
to the Indian number system. Also, write its
The digits in the
number name.
same period are read
Solu on: 3,98,104 together.
 It is read as three lakh ninety-eight thousand

one hundred four.

Mental Maths

Are the commas placed correctly as per the Indian number system?
(a) 6,925,66 (b) 9,98,898 (c) 55,44,68

International Number System

To read large numbers as per the Interna onal number system, we group them into three
periods. Let’s consider the number 8137546.

• Start from the extreme right and make a group of three digits. This is the fi rst group.
It consists of ones, tens and hundreds and is called the ones period. 8137 546

• The second group consists of the next three digits, i.e., thousands, ten thousands
and hundred thousands. It is called the thousands period. 8 137 546
• The third group consists of the next three digits, i.e., millions, ten millions and
hundred millions. It is called the millions period. 8 137 546

Thus, 8137546 is wri en as 8,137,546 and is read as eight million one hundred thirty-
seven thousand fi ve hundred forty-six.

Periods Millions (M) Thousands (Th) Ones (O)
→
Place Million Hundred Ten Thousands Hundreds Tens Ones

Value (M) Thousands Thousands (Th) (H) (T) (O)
(HTh) (TTh)

8,137,546 8 1 3 7 5 4 6

Example 2: Group the given numbers by pu ng commas according to the Interna onal

number system. Also, write the number names.
(a) 43825 (b) 619807

Solution: (a) 43,825 It is read as forty-three thousand eight hundred twenty-fi ve.

(b) 619,807It is read as six hundred nineteen thousand eight hundred
seven.

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