Mathematical puzzles

Puzzles, situation puzzles and recreational mathematics.

situation puzzles and recreational mathematics. Neuron juice
 
 
 

Neuron juice.

The important thing is not to stop questioning. (Albert Einstein.)

  

By José De La Cruz, Tucumán (Argentina)

 

19.- How do we get to twenty , adding one of us, nineteen ?

 

-- Solving the riddle --