My BrainBashers electronic world atlas has developed another fault.
I listed six countries, and how far away each was from England, and here are the results:
Spain 14,000 miles
Fiji 12,000 miles
Germany 18,000 miles
Brazil 16,000 miles
India 16,000 miles
Iceland --,--- miles
Answer
If the sum of the digits is divisible by nine, so is the number.
Add up all of the digits in the number and see if the sum is divisible by 9. If you still can't tell, you can add those digits again to see if the new sum is divisible by 9. You can keep going until you the sum is obviously divisible by 9 or not.
For example, is 486451464 divisible by 9?
Do 4 + 8 + 6 + 4 + 5 + 1 + 4 + 6 + 4 = 42.
Is 42 divisible by 9? Not sure, you can then do:
4 + 2 = 6. Which clearly isn't divisible by 9. So our original number, 486451464, isn't either.
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Puzzle 312
Which of the shapes is identical to the first one?
