Since there are no options to this question, nor have I been able to find any options online, I'll just answer with an interpretation of the excerpt.
Answer:
The theme represented by this line is that if you are an educated person, there is nothing you cannot do. Education is the secret to achieving anything.
Explanation:
<u>In "The Phantom Tollbooth", the pencil is called "a magic staff". Its true magic relies on the person's capacity to use it. If you know Math, if you know languages, if you know any other subject that you like, you can work wonders with a pencil. It is a simple object that can bring to life your ideas, which can even change the world. </u>That is what the Mathemagician reveals as the dialog progresses:
<em>"But it's only a big pencil," the Humbug objected, tapping at it with his cane.
</em>
<em>"True enough," agreed the Mathemagician; "but once you learn to use it, there's no end to what you can do."
</em>
<em>"Can you make things disappear?" asked Milo excitedly.
</em>
<em>"Why, certainly," he said, striding over to the easel. "Just step a little closer and watch carefully."
</em>
<em>After demonstrating that there was nothing up his sleeves, in his hat, or behind his back, he wrote quickly:
</em>
<em>4 + 9 − 2 × 16 + 1 ÷ 3 × 6 − 67 + 8 × 2 − 3 + 26 − 1 ÷ 34 + 3 ÷ 7 + 2 − 5 =
</em>
<em>Then he looked up expectantly. "Seventeen!" shouted the bug, who always managed to be first with the wrong answer.
</em>
<em>"It all comes to zero," corrected Milo.
</em>
<em>"Precisely," said the Mathemagician, making a very theatrical bow, and the entire line of numbers vanished before their eyes. </em>
