Number System
Category : 5th Class
NUMBER SYSTEM
FUNDAMENTALS
Out of these digits, 0 is called insignificant digit and rest are called significant digits.
Numerals
Place value of a digit in HinduArabic System
Periods 
Crores 
Lakhs 
Thousands 
Ones 

Places 
Ten Crores 100000000 
Crores 10000000 
Ten Lakhs 1000000 
Lakhs 100000 
Ten Thousands 10000 
Thousands 1000 
Hundreds 100 
Tens 10 
Ones 1 










Place value of a digit in international system
Periods 
Millions 
Thousand 
Ones 

Places 
Hundred Millions 100000000 
Ten Millions 10000000 
Millions 1000000 
Hundred Thousands 100000 
Ten Thousands 10000 
Thousands 1000 
Hundreds 100 
Tens 10 
Ones 1 










Inserting Commas
Example:
10 Lakhs = 10, 00, 000
10 Million = 10,000,000
Fundamental Operation of Numerals
Example: \[31\times 1=31,\,\,72\times 0=0\]
Division (+)
a=Divisor, b= Dividend, c= Quotient, d= Remainder
Example:
Divisibility Test
If the last digit of a number is even or 0 then it is divisible by 2
Example: 3240, 3296 etc.
Example: 3246, 4122 etc.
Example: 1800 is divisible by 4 because its last two digits are 0.1864, Is divisible by 4 because 64 is divisible by 4.
Example: 1350, 1355, 6525, 1800. All these numbers are divisible by 5.
Example: 324696.
In 324696, the last digit is 6, which is even number, so it is divisible by 2. Sum of 324696 Is 30, 30 is also divisible by 3. Therefore, 324696 is divisible by 6.
Example: 2401
Again,
Which is divisible by 7. Hence, 2401 is divisible by 7.
Example: 12000, 20416. These both numbers are divisible by 8.
Example: 8937, 48231 etc. Both numbers are divisible by 9, because the sum of digits of the numbers is divisible 9.
Example: 1710, 2350 etc.
Example: 13312024, 8030 etc.
In 13312024 sum of digits at odd places= 1 + 3 + 2 + 2 = 8
Sum of digits at even places = 3 + 1 + 0 + 4 = 8. So, difference =0, hence, 13312024 is divisible by 11.
In 8030, sum of digits at odd places= 8 + 3 = 11, sum of digits at odd places = 8 + 3 = 11, sum of digits at even places= 0 + 0 = 0
\[\therefore \] Difference =11 ? 0 = 11, which is divisible by 11, hence 8030 is divisible by 11.
BODOMAS Rule
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