Page 17 - ICSE Math 6

1 Numbers

Key Concepts

• Numeral, Numeration and Hindu-Arabic System of • Expanded Form of a Number
Numeration • Comparison and Formation of Numbers
• Face Value and Place Value • Operations on Large Numbers
• Indian and International Place Value Charts • Estimation (in Sum, Difference, Product and Quotient)

Numbers are the building blocks of Mathematics. They help us to count, measure, compare, order and
label things. We use numbers everywhere in our daily life. For example, counting number of students
present in a class, labeling a vehicle’s number plate, measuring the weight in kilograms, etc.

Numeral
Maths Info
Numerals are symbols used to represent numbers. In Hindu-Arabic
system of writing numbers, a numeral is formed using a single digit Hindu-Arabic System of writing
numbers uses ten digits or
or group of digits. For example, 3, 15, 735 and 1,125 are numerals. figures to form numerals and
they are: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
Hindu-Arabic System of Numeration

The process of reading, writing and naming numbers in words, in a given system is called numeration.
The decimal system which we use in Mathematics is the Hindu-Arabic system of numeration. It is
named so because it was originated by the Hindu mathematicians, then it was further developed by
the Arabs and finally it was introduced to western Europe. This system uses 10 digits (from 0 to 9)
and is based on the concept of place value.
In this system, Maths Info
Ten ‘ones’ make one ‘ten’, i.e., 10 × 1 = 10 Hindu-Arabic number system is

Ten ‘tens’ make one ‘hundred’, i.e., 10 × 10 = 100 also known as denary system
Ten ‘hundreds’ make one ‘thousand’, i.e., 10 × 100 = 1,000 and base 10 system.

Face Value

The face value of a digit, at any place in a numeral is the value of the digit itself. Face value is also
known as true value. For example, the face value of 9 in both 900 and 56,097 is 9, irrespective of its
position in the two numerals.

Place Value

The place value of a digit in a numeral is the product of its face value and the value of its place in
the given numeral. Place value is also known as local value. For example, consider the numeral 986.
The digit 6 is at ones place. So, its place value is 6 × 1 = 6.
The digit 8 is at tens place. So, its place value is 8 × 10 = 80.

The digit 9 is at hundreds place. So, its place value is 9 × 100 = 900.

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