00:01
We want to find out how many different letter combinations we can take from this word or, you know, made up word asked with if we're taking five of the seven letters.
00:10
So there's a quick algebraic way and then we definitely understand the deeper concept as well.
00:15
So if we're going to choose a five letter combination, the order of them does matter.
00:20
So for example, if we took the letters, you know, let me just take the first five letters, asqui, that's different than if i said asqi.
00:30
You.
00:31
So the order of them does matter.
00:33
Since the order of them does matter, a simple way to calculate this, i like to always do a fill in the blanks with the students i teach.
00:40
And i say, okay, if we're starting from scratch, how many letters are there to choose from? so we have one, two, three, four, five, six, seven letters.
00:47
So there's seven possibilities for that first letter.
00:50
If, for example, we choose h is our first letter, we don't have seven choices anymore.
00:54
We have six possibilities for what's next.
00:57
So as you continue this pattern, after two letters are gone, there'd be five left, then four left, then three left...