0
While it is possible to come up with divisibility rules for any number, some divisibility rules are more complicated than others, and in some cases it becomes easier to just carry out the division.
A rule that works for 8 is: If the last three digits of a number are divisible by 8, then the entire number is divisible by 8.
For 7: Separate a number's last three digits, and divide from the remaining number. If the result is divisible by 7, the original number is divisible by 7. For example, in 31969, separate as 31; 969. Subtracting the second part from the first will give you a negative number, but you can also subtract the other way: 969 - 31. Since the result is divisible by 7, the original number also is.
This SAME rule also works for 11 and 13, and is based on the fact that 7, 11 and 13 are factors of 1001.
What else can I help you with?
What are the divisibility rules for 72?
If the last 3 digits are divisible by 8 and the sum of the digits are divisible by 9.
What are the divisibility rules from 1-25?
26
What are the divisibility rules to find at least four factors of the number 312?
A number is a multiple of 312 if it's a multiple of 3, 8 and 13 at the same time
What divisibility rules can be used to find the factor pairs of 80?
Those for 1, 2, 4, 5 and 8.
What are the divisibility rules for the number two?
Any multiple of two must end in 0, 2, 4, 6 or 8.
What does it means to use the divisibility rules to find factor pairs for eighty?
Factors are divisors. If you know the divisibility rules, you know that 80 is divisible by 1, 2, 4, 5 and 8. If you divide 80 by those numbers, you find the other half of the factor pairs.
How can you tell if 53 is a prime number?
The square root of 53 is between 7 and 8. If 53 was composite, half of its factors would be less than its square root. By the rules of divisibility, we know that 53 is not divisible, by 2, 3, 4, 5, 6 or 7. It has to be prime.
What are the divisibility rules for 7 and 8?
There is one for 7, although it is not very useful. Take the last digit, truncate it and double it. Then subtract it from the rest. If the resulting number is divisible by 7, so was the original. For 8, if the last 3 digits are divisible by, so is the number in question. For example, 72248 is divisible by 8 because 248 is. And 259 is divisible by 7 because 9 times 2 is 18, and 25 minus 18 is 7... Voila!
What is the divisibility rule for 4 7 8?
4- last two digits are a multiple of 4 7-take the last digit and subtract it from the rest of the number and if multiple of 7 (including 0) 8- last three digits are multiple of 8
Is 45600 divisibility by 8 or 9?
8, yes. 9, no.
What are the Divisibility rules of 14 15 18?
14...Checking for divisibility by 14 would combine the rules for 2 and 7, since 2x7 = 14The rule for 2 is that the last digit of the number is even (0,2,4,6 or 8).There is no real rule for 7, but there is one way of testing divisibility by 7 that I have come up with, although rather complicated. First, write your number, then beneath it, under each digit from right to left, write out the numbers 1,3,2,6,4,5 in that order and keep repeating the sequence until each digit of your number has another digit beneath it. Use only the amount of digits needed. Then, multiply each digit of your number by the digit beneath it, and add all of these new numbers. If the number you get is a multiple of 7, the number you began with was also a multiple of 7.Example for 7:We are checking 3192847 for divisibility by 7...3 1 9 2 8 4 71 5 4 6 2 311x3 + 5x1 + 4x9 + 6x2 + 2x8 + 3x4 + 1x7= 3 + 5 + 36 + 12 + 16 + 12 + 791We can test 91 again to find divisibility...9 13 13x9 + 1x1 = 2828 is a multiple of 7 (it is 4 x 7), so 91 and 3192847 must also be multiples of 7. 3192847 is actually 456121 x 7.If both of these tests work, the number must be a multiple of 14.15...Divisibility by 15 can be tested by combining the rules for 3 and 5.The rule for 3 is that the sum of all the digits in the number is a multiple of 3.The rule for 5 is that the number ends in 5 or 0.If both of these tests work, the number must be a multiple of 15.18...Checking for divisibility by 18 combines the divisibility rules for 2 and 9.Once again, a number is divisible by 2 if its last digit is even.A number is divisible by 9 if the sum of its digits is a multiple of 9.If both of these tests work, the number must be divisible by 18.
What is divisibility rule?
What is the divisblity rule by 8
