a number is divisible by 9 if the sum of the digits is divisible by 9.
3 and 9. And they divide into 123456789 whether or not you use divisibility rules!
The divisibility rules for a prime number is if it is ONLY divisible by 1, and itself.
If the last 3 digits are divisible by 8 and the sum of the digits are divisible by 9.
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.
1 3 9 19 57 95 171 285 855
You have to use the rules of 4 and 9 Using the rules of 2 and 18 won't work because the smallest common multiple of 2 and 18 is 18 not 36. 3 and 12 won't work either because the smallest common multiple of 3 and 12 is 12 not 36. However 4 and 9 does work because their biggest common divisor is 1 so multiplying them works. The biggest common divisor of 2 and 18 is 2 and the biggest common divisor of 3 and 12 is 3
12
You can always check on the divisibility of a number by dividing it into another number. But if you know the divisibility rules, you can get that information easier and faster.
i think divisibility rules help with fractions because it helps you reduce the fraction to make i a simple fraction.
Three
Divisibility rules have been developed and refined by mathematicians over the centuries. It is difficult to attribute the invention of divisibility rules to a specific individual. However, some early rules can be traced back to ancient civilizations like the Egyptians, Babylonians, and Greeks. These rules were further expanded upon and formalized by various mathematicians throughout history.
bogo mo!