What is the largest composite number less than 20 (17,18,19,20)

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Answer

    18

Explanation

Before starting let us see what is the composite number?
"A number that can be divided exactly by numbers other than 1 or itself is called a composite number".
So according to the defination of composite number are 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, ....

Find the prime number from 1 to 100 just in 5 second (MATH PRIME NUMBER SHORTCUT TRICK from 1 to 100 number)

Find a large number "A" is prime number or not (MATH PRIME NUMBER SHORTCUT TRICK By using Square Root method)

Now the question is what is the largest composite number less than 20 ? And given four option are 17,18,19,20.

Here 20 will not be included because we need less then 20.
Here 19 also will not be included because 19 is not composite number it is a prime number.
Here 18 is composite number also less then 20. So 18 is the required composite number.
Here 17 is also prime number?

So final answer is 18 is the required composite number which is also less then 20.

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NUMBERING SYSTEM (MATH SHORTCUT TRICKS)

Find the prime number from 1 to 100 just in 5 second (MATH PRIME NUMBER SHORTCUT TRICK from 1 to 100 number) ?

Find a large number "A" is prime number or not (MATH PRIME NUMBER SHORTCUT TRICK By using Square Root method) ?

Find the composite number from 1 to 100 just in 5 second (MATH COMPOSITE NUMBER SHORTCUT TRICK from 1 to 100 number) ?

NUMBERING SYSTEM QUESTION

Is zero even number or odd number (Even, Odd, Both, Neither even nor odd)...?

What is the lowest odd prime number (2, 3, -2, -3)...?

What are the consective prime number (2 and 3, 5 and 7, 11 and 13, all above)...?

Which number is prime number (1, 39, 49, None)...?

1 is prime or composite number (Prime, Composite, both, Neither Prime nor composite)..?

Give me numbers which are neither prime nor composite (0, 1, 0 and 1, None)?

All non prime number are also the composite number. (True or False)?

Which number neither prime nor composite (1, 29, 39, None)...?

What is the largest composite number less than 20 (17,18,19,20). ?

What is largest composite number less then 30 (23, 25, 28, 29)?

The number 4, 6, 8, 9, ... are (odd, even, prime, composite number) ...?

All even number greater then 2 are composite number (True, False)... ?

How many prime number are between 10 and 30 (5, 6, 7, 8)?

How many prime number are between 1 and 100 (25, 27, 29, 31)?

Which of the following is prime number (703,731,797,729)...?

MATH SHORTCUTS

Addition Shortcuts

Division Shortcuts

SHORTCUT TRICKS (Division)

Divisible by 2 Shortcut trick

Divisible by 3 Shortcut trick

Divisible by 4 Shortcut trick

Divisible by 5 Shortcut trick

Divisible by 6 Shortcut trick

Divisible by 7 Shortcut trick

Divisible by 8 Shortcut trick

Divisible by 9 Shortcut trick

Divisible by 10 Shortcut trick

SHORTCUT TRICKS (Prime Number)

Find the prime number from 1 to 100 just in 5 second (MATH PRIME NUMBER SHORTCUT TRICK from 1 to 100 number) ?

Find a large number "A" is prime number or not (MATH PRIME NUMBER SHORTCUT TRICK By using Square Root method) ?

Find the composite number from 1 to 100 just in 5 second (MATH COMPOSITE NUMBER SHORTCUT TRICK from 1 to 100 number) ?

SHORTCUT TRICKS (Prime Number)

Find the prime number from 1 to 100 just in 5 second (MATH PRIME NUMBER SHORTCUT TRICK from 1 to 100 number) ?

Find a large number "A" is prime number or not (MATH PRIME NUMBER SHORTCUT TRICK By using Square Root method) ?

Find the composite number from 1 to 100 just in 5 second (MATH COMPOSITE NUMBER SHORTCUT TRICK from 1 to 100 number) ?

Worksheets (Solved)

Matrix Logarithm

Trigonometric Identities

Application of Trigonometry

Integration