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Reducing_a_Large_Number

# Reducing_a_Large_Number - For the number 7 you just need to...

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Reducing a Large Number There are a couple of tricks that can be used thanks to a 10-cent book on Math magic I picked up at a garage sale several years ago (ha, ha, ha). Reducing a large number First, look at the last number of each that is the numerator and denominator. If they are both even you can always start with dividing both by 2. Don't get adventurous and look for the biggest number, start with the 2 and it will work out just fine. Second, if one or the other ends in a 5 or a 0 you can always divide by 5. Based on the above we have found ways of doing it for numbers ending in 0, 2, 4, 5, 6, & 8. That leaves 3, 7 & 9. (1 doesn't count)
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Unformatted text preview: For the number 7, you just need to use your calculator on that one. But for 3 & 9, I have a different approach. First, if a 9 can go into a larger number you know that a 3 can since a 9 is a multiple of 3. But to see if 3 can go into a number a clever little way was given to me from that book. Let's take an example. ..say the number 7, 017. On the surface it looks like there is nothing that would go into it evenly. ..WRONG!!!! Add the digits of the number, that is 7 + 0 + 1 + 7 and it totals 15. If this number is divisible by 3 then the entire number is! Cute trick....
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