Always End With 1089
Add two number together and always end with 1089.
Here is How:
|Pick a three digit number.The three numbers used must be different*. i.e. 123||Reverse that number. 123 becomes 321|
|Take the smallest three digit number from the largest.|
321 - 123 = 198
|Take the answer and reverse that number. 198 becomes 891|
|Add that number to the answer of the subtraction. 891 + 198 = 1089|
The answer will be 1089!
So Why does it do this?
Why is it always 1089
(This is the reasoning behind Always End With 1089)
You will need a little bit of algebra.
|Represent the number with ABC|
|Reverse this to get CBA|
|Remember that A is Hundreds B is tens and C is units|
Take CBA from ABC like this
|Now here is the trick: subtract 1 Hundred, and add 9 Tens and 10 Ones (-100, +90, +10 = 0, so won't change answer):|
|Last Step: Reverse the answer and add the two numbers together.|
As predicted the answer was 1089