Unformatted text preview: 6. No short method has been found for determining whether a number is divisible by 7. 7. A number is divisible by 8 if the number formed by the three righthand digits is divisible by 8. For example, the three righthand digits of the number 54,272 form the number 272, which is divisible by 8. Therefore, we know that 54,272 is divisible by 8. 8. A number is divisible by 9 if the sum of its digits is divisible by 9. For example, the sum of the digits of 546,372 is 27, which is divisible by 9. Therefore we know that 546,372 is divisible by 9. Practice problems. Check each of the following numbers for divisibility by all of the digits except 7: 1. 242,431,231,320 2. 844,624,221,840 3. 988,446,662,640 4. 207,634,542,480 Answers: All of these numbers are divisible by 2, 3, 4, 5, 6, 8, and 9....
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 Spring '11
 Espisito
 Fraction, Numerical digit, Elementary number theory

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