How can adding help me with subtracting?

NARRATOR: Hello you two, I see you’re juggling plasmoids.

SNOOT: (ALIEN LANGUAGE)

NARRATOR: Very impressive.

It looks like you’ve got 1… 2… 3 plasmoids mastered.

SNOOT: (ALIEN LANGUAGE)

NARRATOR: Do you think you could manage 4?

OK then Fin, let’s see you.

Snoot, why don’t you give Fin one of your plasmoids?

Thank you Snoot.

So you had 3 plasmoids, and you gave one away.

That’s left you 2 to juggle with.

Easy!

Now your turn Fin.

You had 3 plasmoids, then Snoot added one, so now you’ve got 4.

Go for it.

Maybe that wasn’t such a good idea?

Maybe give that extra plasmoid back?

SNOOT: (ALIEN LANGUAGE)

NARRATOR: That’s quite right Snoot.

First you had 3 plasmoids each, then you took one of yours away leaving you with 2 and added it to Fin’s, giving Fin 4.

Then Fin took one of the 4 away and added it to your 2, giving you 3 plasmoids each again.

FIN: (ALIEN LANGUAGE)

NARRATOR: Exactly right Fin.

Adding one is the opposite of taking away one.

3 add 1 equals 4, and if you turn that sum around, you get 4 minus 1 equals 3.

You could do that with any numbers you like.

For example, 4 add 2 equals 6, and 6 minus 2 equals 4.

BOTH: Aha!

NARRATOR: Now then, who’s ready for some more juggling?

PLIMBLE: Plimble!

NARRATOR: Ah… 3 balls is still very good.