Numbers are the foundation of arithmetic. They are a universal language applied globally for measurements and identifying quantities. We deal with numbers every day for calculating time, distance, charges, discounts, etc. From cooking to space travel, numbers are present everywhere. In this article, we will learn about numbers definition, properties, representation, types and place value along with sample problems. We will also cover many related topics to help you recognise numbers accurately.
Table of Contents
A number is a value used to measure and represent quantities. A wide variety of mathematical symbols are used to count, measure, and perform calculations. By definition, all mathematical digits and values used to symbolise an amount or order are called numbers. For example: 0, 1, 2, 3, -1, ½, 2 are different types of numbers. Numbers not only help us to describe things clearly but they also represent advanced scientific data precisely. Along with mathematics, they are applied in the field of engineering and technology to solve real-life problems.
The numbers have different properties and based on these properties, they are categorized into different types. Below is a clear explanation of each type of number with an example:
Natural numbers are positive integers that start from 1 and continue till infinity. i.e., they start from 1, 2, 3, 4... till infinity.
The set of natural numbers is denoted by 'N', where N = {1, 2, 3, 4...}
Properties of Natural Numbers
● They begin from 1 and move on to infinity.
● Symbol: ℕ
● Examples: 1, 2, 3, 4, 5, ...
Whole numbers are positive integers that start from 0 and go to infinity. i.e., they start from 0, 1, 2, 3, 4... till infinity.
Properties of Whole Numbers:
● Whole numbers encompass all natural numbers and 0.
● Symbol: W
● Examples: 1, 2, 3, 4, ...
Integers are numbers that include all whole numbers, along with their negative opposite.
● Symbol: ℤ
● Examples: -3, -2, -1, 0, 1, 2, 3
Numbers that are expressed as a fraction, i.e., a/b, in which 'a is the numerator and 'b' is the denominator and b ≠ 0.
● Examples:1/2, -3/4, 5/1
Irrational numbers are numbers that cannot be expressed as a fraction.
● Examples: √2, π, e
Real numbers are numbers that include both rational and irrational numbers.
● Examples: -5, 0, 2/3, √2
Complex numbers are numbers that include an actual and an imaginary component.
● Format: a + bi
● Example: 3 + 2i
Natural numbers refer to the basic numbers used in counting different quantities. They start from 1 and continue till infinity.
● They do not include 0 or negative numbers.
● Used for regular counting like “2 apples”, “5 pencils”, and many others.
● Examples: 1, 2, 3, 4, …
● Whole numbers encompass 0, together with all natural numbers.
● Examples: 0, 1, 2,3, 4, 5, ...
The numbers are used in variety of ways in differnt number systems using various digits, aplha-numeric values and symbols
Here are some common types of number systems:
1. Decimal (Base 10)
2. Binary (Base 2)
3. Octal (Base eight)
4. Hexadecimal (Base 16)
Learning to read/write numbers in words is an important skill required for formal communication. Below are a few examples of how numbers are represented in words:
● 1 → One
● 12 → Twelve
● 25 → Twenty-Five
● 100 → One hundred
● 123 → One hundred twenty-three
A number series is a set of numbers arranged in a specific order.
Arithmetic Series: Common Distinction
Example: 2, 4, 6, 8, ... (distinction = 2)
Geometric Series: Common ratio
Example: 3, 6, 12, 24, ... (×2)
Fibonacci Series: Sum of preceding numbers
Example: 0, 1, 1, 2, 3, 5, 8,...
Type of Number |
Includes |
Examples |
Natural Numbers |
Counting numbers |
1, 2, 3, 4 |
Whole Numbers |
Natural numbers + 0 |
0, 1, 2, 3 |
Integers |
Whole numbers + negatives |
-2, -1, 0, 1, 2 |
Rational Numbers |
Fractions or decimals |
1/2, 0.25, -¾ |
Irrational Numbers |
Non-fractions |
√2, π, e |
Real Numbers |
Rational + Irrational |
-5, 0.5, √3 |
Complex Numbers |
Real + Imaginary parts |
3 + 2i, -1 + 5i |
Some unique numbers have unique mathematical properties:
For Examples: 2, 3, 5, 7, 11
For Examples: 4, 6, 8, 9
For Examples: 2, 4, 6, 8
For Examples: 1, 3, 5, 7
For Example: 6 has factors 1, 2, 3 and sum of 1 + 2 +3 = 6
Understanding the properties of numbers helps to easily solve equations.
a + b = b + a
a × b = b × a
(a + b) + c = a + (b + c)
(a × b) × c = a × (b × c)
a × (b + c) = a × b + a × c
a + 0 = a
a × 1 = a
a + (-a) = 0
a × (1/a) = 1 (if a ≠ 0)
Incorrect. Zero isn't a real quantity.
False. 1 isn't high or composite.
Not continually. π and √2 are decimal, however irrational.
Wrong. Negative numbers are actual numbers.
Only if both the numerator and denominator are integers.
Unique combos of digits used for identification.
Currency is all approximately numbers – charge, interest, income.
Clocks and calendars use numbers to represent time and dates.
Barcodes, OTPs, and passwords use numbers.
Player information, scores, and ratings depend upon numbers.
Classifying Numbers (Types)
Problem: Classify the numbers 0, −7, 2/5, 3.1416, √16, √2 into Natural, Whole, Integers, Rational, Irrational, Real.
Solution:
• 0 → Whole, Integer, Rational, Real (not Natural in most definitions).
• −7 → Integer, Rational (−7/1), Real.
• 2/5 → Rational (ratio of integers), Real.
• 3.1416 → Terminating decimal, Rational, Real.
• √16 = 4 → Natural, Whole, Integer, Rational, Real.
• √2 → Non-terminating, non-repeating, Irrational, Real.
Answer:
Natural: {4}
Whole: {0, 4}
Integers: {−7, 0, 4}
Rational: {−7, 0, 2/5, 3.1416, 4}
Irrational: {√2}
Real: {all listed}
Using Properties to Simplify (Commutative, Associative, Distributive)
Problem: Simplify 25×48 + 25×52 and 18 + (−7) + (−13).
Solution:
• 25×48 + 25×52 = 25(48 + 52) [Distributive]
= 25×100 = 2500.
• 18 + (−7) + (−13) = (18 − 7) − 13 [Associative]
= 11 − 13 = −2.
Also, 7×9 = 9×7 [Commutative of multiplication].
Answer: 2500 and −2.
GCD/LCM via Prime Factorization (Application)
Problem: Find GCD and LCM of 84 and 126. Then solve: Two alarms ring every 84 minutes and 126 minutes. If they ring together now, after how many minutes will they ring together next?
Solution:
84 = 2² × 3 × 7
126 = 2 × 3² × 7
GCD = 2¹ × 3¹ × 7¹ = 42
LCM = 2² × 3² × 7 = 252
Application: They ring together every LCM minutes, which is 252 minutes.
Answer: GCD = 42, LCM = 252, Next together in 252 minutes.
Prime vs Composite (Divisibility Tests)
Problem: Decide if 221 is prime or composite.
Solution:
• Not even, since 221 is not a multiple of 2.
• The sum of the digits 2+2+1=5, which is not a multiple of 3.
• The last digit is not 0 or 5, so it is not a multiple of 5.
• Test primes up to √221, about 14.8, checking 7, 11, 13.
• 221 ÷ 7 = 31 remainder 4 (not divisible).
• 221 ÷ 11 = 20 remainder 1 (not divisible).
• 221 ÷ 13 = 17 exactly, so 221 = 13 × 17.
Answer: 221 is composite (factors 13 and 17).
Rational Numbers & Scientific Notation (Applications)
Problem A: Express 0.375 and 0.3̅ as fractions.
Problem B: Compute (3.2×10⁶) + (7.5×10⁵).
Solution:
A1) 0.375 = 375/1000 = 3/8 (simplified).
A2) Let x = 0.3̅, then 10x = 3.3̅. Thus, 10x − x = 3, leading to 9x = 3 and x = 1/3.
B) (3.2×10⁶) + (7.5×10⁵) = (3.2×10⁶) + (0.75×10⁶) = 3.95×10⁶.
Answer: 0.375 = 3/8; 0.3̅ = 1/3; sum = 3.95×10⁶.
The international numbers are tremendous, numerous, and critical. From understanding what natural numbers and complete numbers are to exploring varieties of numbers, their properties, and real-life applications, this guide offers a complete introduction to numbers and the variety of numbers.
Mastering numbers lays the foundation for all math topics. Whether you are just starting or deepening your understanding, continue exploring and practising to strengthen your numerical talents.
Answer: The numbers 1 to 100 are natural numbers starting from 1 and ending at 100.
Answer: The smallest whole number from 1 to 100 is 1.
Answer: Odd numbers from 1 to 100 are those not divisible by 2, like 1, 3, 5, ..., 99.
Answer: From 1 to 100, the biggest natural number is 100.
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