Add together all the digits in the number and see if the sum is divisble by 3.
(example: 1551------- 1+5+5+1=12----12/3=4-------1551/3=517
Its factors are: 1, 3, 71 and 213
Divisibility rules help you find the factors of a number. Once you've found the factors for two or more numbers, you can find what they have in common. Take 231 and 321. If you know the divisibility rules, you know that they are both divisible by 3, so 3 is a common factor.
It is divisible by any of its factors which are: 1, 3, 431 and 1293
It is divisible by any of its factors which are: 1, 3, 31 and 93
It is divisible by any of its factors which are: 1, 3, 31 and 93
Factors go into numbers, numbers go into multiples. Divisibility shows what factors come out of what multiples.
1, 2, 3 and 4
The least 4 factors of 144 are 1, 2, 3, and 4 .
A number is divisible by 15 if it is divisible by the prime factors of 15, that is, 5 and 3.
use divisibility rules to find at least four factors of the number 19
With the common divisibility rules, you can quickly see that it is divisible by 5, and by 9 (3 x 3). If you divide 225 by each of these numbers, you should be able to get the remaining factors quickly, as well.
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.