Topic: divisibility by 9 list of topics
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8 items are filed under this topic.

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	4821x14y is an 8-digit number divisible by 72		2014-08-06
		From RAYA: if 4821x14y is an 8-digit number divisible by 72. How many values can x and y take? Answered by Penny Nom.
	A 4 digit number		2014-04-04
		From LIM: "A" is a 4 digit number formed by all the numbers from 1 to 4. When "A" is divided by 9, the remainder is the biggest possible value. What is the biggest value of A? Answered by Chris Fisher.
	An even multiple of 27		2011-02-01
		From parth: the 6 digit # 63x904 is an even multiple of 27 what is X Answered by Penny Nom.
	Powers		2010-10-20
		From dylan: how do you write 20736 in exponential form .same for 1728 and 50625. is there a formula to figure out how to express large know numbers in exponential form. Answered by Penny Nom.
	Divisibility rules		2001-09-07
		From A student: Why is it that when you add the digits of a number you can tell what the multiples of that number are. Example: 12131313111, 1+2+1+2+1+3+1+1+1=18, therefore 12131313111 is divisble by 2, 9, 18, & 3 because those numbers are divisble by 18. Answered by Penny Nom.
	Divisibility by 9		2000-10-24
		From Kelera: If the sum of the digits of a number is divisible by 9, then the number itself it divisible by 9. Why is that? How do you explain this? Answered by Penny Nom.
	Divisibility by 3		2000-03-24
		From Pat Walsh: W hy does it work when you add the digits of a number then divid by three to see if the number is divisible by three Answered by Penny Nom.
	Divisibility by 9		1999-02-21
		From Razzi: I've been having a hard time trying to solve the following problem and I was wondering if you could help me. For any positive integer a let S(a) be the sum of its digits. Prove that a is divisible by 9 if and only if there exist a positive integer b such that S(a)=S(b)=S(a+b). Answered by Chris Fisher and Harley Weston.

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