To test divisibility for 20, you need to use the tests for divisibility by 4 and 5.
The test for divisibility by 4 is that the last 2 digits of the number, given as a 2-digit number, are divisible by 4.
Example for 4:
We are testing the number 11042.
42/4 = 10.5 which is not a whole number. Therefore 11042 is not divisible by 4.
The test for divisibility by 5 is that the last digit of the number is either 5 or 0.
There is no easy rule for divisibility by 34.
By tautology. If it did not work, it would not be a divisibility rule!
why does the divisibility rule work for 4
There are two ways of answering this.Check the number for divisibility by 2.Check the quotient for divisibility by 2.Check the quotient for divisibility by 2.Check the quotient for divisibility by 2.Check the quotient for divisibility by 2.Check the quotient for divisibility by 2.For large numbers, the check can be restricted to the number formed by the last six digits.
there is a divisibility for 24 the rule is you can divide 24 as 6 and 4 i think
all even numbers
Every number has a test for divisibility. The issue is that the tests get more complicated as the divisor increases. For primes up to 50, see either of the attached links.
If the number is also divisible by 2 and 3
The number must end in 00, 20, 40, 60 or 80.
It is divisibility by 3 and divisibility by 5.Divisibility by 3: the digital root of an integer is obtained by adding together all the digits in the integer, with the process repeated if required. If the final result is 3, 6 or 9, then the integer is divisible by 3.Divisibility by 5: the integer ends in 0 or 5.
A number is divisible by 6 if the number is divisible by 2 AND 3.
Divisibility test for 3 : the sum of digits of the given number must be a multiple of 3 Divisibility test for 4 : the number formed by last 2 digits must be a multiple of 4.
The number must end in one of the following: 00, 20, 40, 60, 80.
Just doing the division is simpler, in most cases.