Hi Andrew Sittner (Andrew Sittner), we edited your question title and the description.

✅ Corrected grammatical errors in the title
✅ Used markdown to highlight code snippet in the question description.

The code

function learning(x,y) { 
  return function inLearning(z){ 
     return console.log(x) + console.log(y) + console.log(z); 
  }; 
};

creates a function whose duty is to return on its turn a function that does something. In this case it prints the received parameters (or sent arguments). A call as learning(1, 2)(3) will show:

1
2
3

Try to experiment with different calls: learning(2)(3), learning(1, 2)(), learning(1,2,5)(3,4), learning()(5), etc.

It is a pattern that should help eliminating extra function executions, and avoid repetitions of code that ideally would then be easier to understand and maintain.

A good starting point to understand this kind of pattern is the JavaScript Functions that Return Functions post.