PDF chapter test TRY NOW

Fill in the following surprise number as per the instruction :
 
Pick the number from the dropdown:
 
Double the picked number:  \(×\)  \(=\)
 
Again double it:  \(×\) \(2 =\)
 
Add the number you picked first to the answer:  \(+\)  \(=\)
 
Now again double it:  \(×\) \(2 =\)
 
Divide by \(10\):  ÷ \(10 =\) .
 
thinking-clipart-cartoon-1.png
 
Hurray!!!
 
Both the start and end numbers are the same.... 
 
How it works? Let's see the explanation.