Question 1006037
If you take a number 
<pre>
Call this original number by a letter, say,

      N
</pre>
and add a zero to the right 
<pre>
To annex a zero on the right is to multiply it by 10.

So this is 

    10N
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and subtract the result from 143, 
<pre>
That gives 

   143 - 10N
</pre>
you’ll get three times the original number. 
<pre>
So we have the equation

   143 - 10N = 3N
</pre>
What is the number?
<pre>
   Add 10N to both sides:

     143 = 13N

Divide both sides by 13

     11 = N

Edwin</pre>