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To find out if a number is divisible by seven, take the last digit, double it, and subtract it from the rest of the number.
Example: If you had 203, you would double the last digit to get six, and subtract that from 20 to get 14. If you get an answer divisible by 7 (including zero), then the original number is divisible by seven. If you don't know the new number's divisibility, you can apply the rule again. Source~http://mathforum.org/k12/mathtips/division.tips.html But with incrediby large numbers you're just better off just dividing to see.
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Is 27 divisible by 3?
27 is divisible by three because the sum of 2 and 7 is divisible by three. However, this trick only works with the numbers 3 and 9. 27 divided by 3 is 9.
What number is divisible by 3 1324 or 2463?
2463. The trick is that a number is divisible by 3 if and only if the sum of its digits is divisible by 3. 1+3+2+4 = 10 (not divisible by 3), while 2+4+6+3 = 15 (divisible by 3).
What is 207 divisible by?
This is an easy one, if you know a little trick -> add up the digits ! 2 + 0 + 7 = 9. Is this divisible by 3 ? Yes ! then 207 is divisible by three. Divide it, you get 69. Add the digits = 15, also divisible by 3. Divide again, you get 23. So, 207 is divisible by 3 3 23.
What is the smallest number divisible by 1 3 5 7 9?
Well, everything is divisible by 1. If something is divisible by 9, then its divisible 3 so you dont need to worry about those two. It's 315.
If a natural number is divisible by 7 then it is divisible by 14?
No, 7 is a natural number divisible by 7 and not 14 for example. In fact every odd multiple of 7 (i.e. 7 times 1,3,5,7,...) is divisible by 7 and not 14.
