Or any type of two flavors: banana, chocolate, banana, vanilla, or chocolate, vanilla,

Or every three seasonings (no the isn"t greedy),

Or you could say "none at all thanks", i m sorry is the "empty set":

Example: The set alex, billy, casey, dale

Has the subsets:

alexbillyetc ...

You are watching: How many subsets in a set with 7 elements

It likewise has the subsets:

alex, billyalex, caseybilly, daleetc ...

Also:

alex, billy, caseyalex, billy, daleetc ...

And also:

the entirety set: alex, billy, casey, dalethe north set:

Now let"s start with the Empty collection and relocate on increase ...

TheEmpty Set

How countless subsets walk the empty set have?

You can choose:

the totality set: the empty set:

But, hang on a minute, in this case those room the same thing!

So theempty collection really has actually just 1 subset (whichis itself, the empty set).

It is prefer asking "There is nothing available, therefore what carry out you choose?" price "nothing". That is your only choice. Done.

ASet through One Element

The collection could be anything, however let"s simply say that is:

apple

How numerous subsets go the set apple have?

the entirety set: applethe empty set:

And that"s all.Youcanchoose the one element, or nothing.

So any set with one element will have 2 subsets.

ASet through Two Elements

Let"s include another aspect to our example set:

apple, banana

How many subsets go the collection apple, banana have?

It might have apple, or banana, and also don"t forget:

the entirety set: apple, bananathe empty set:

So a collection with two aspects has 4 subsets.

ASet With three Elements

apple, banana, cherry

OK, let"s be an ext systematic now, and also list the subsets by how many elements they have:

Subsets v one element: apple, banana, cherry

Subsets through two elements: apple, banana, apple, cherry, banana, cherry

And:

the entirety set: apple, banana, cherrythe north set:

In fact we could put that in a table:

 List Number that subsets zero elements 1 one element apple, banana, cherry 3 two elements apple, banana, apple, cherry, banana, cherry 3 three elements apple, banana, cherry 1 Total: 8

(Note: walk you watch a sample in the numbers there?)

Now try to do the same for this set:

apple, banana, cherry, date

Here is a table for you:

 List Number that subsets zero elements one element two elements three elements four elements Total:

(Note: if friend did this right, there will certainly be a sample to the numbers.)

Setswith 5 Elements

And now:

apple, banana, cherry, date, egg

Here is a table because that you:

 List Number of subsets zero elements one element two elements three elements four elements five elements Total:

(Was over there a sample to the numbers?)

Setswith six Elements

apple, banana, cherry, date, egg, fudge

OK ... We don"t need to complete a table, because...

How numerous subsets are there for a collection of 6 elements? _____How numerous subsets space there because that a set of 7 elements? _____

AnotherPattern

Now let"s think around subsets and also sizes:

Theemptyset hasjust 1subset: 1A set with one facet has 1 subset through no elements and 1subset with one element: 1 1A set with twoelements has 1 subset v no elements, 2 subsets through one element and also 1 subset v two elements: 12 1A set with threeelements has actually 1 subset through no elements, 3 subsets with oneelement, 3 subsets v two elements and also 1 subset through threeelements: 1 3 3 1and therefore on!

Do you identify thispattern that numbers?

They room the number from Pascal"sTriangle!

This is very useful, due to the fact that now girlfriend can examine if you have the right variety of subsets.

Note: the rows begin at 0, and likewise the columns.

Example: because that the collection apple, banana, cherry, date, egg you list subsets of length three:

apple, banana, cherryapple, banana, dateapple, banana, eggapple, cherry, egg

But that is only 4 subsets, how many should there be?

Well, you are picking 3 the end of 5, so walk to row 5, position 3 the Pascal"s Triangle (remember to begin counting at 0) to discover you need 10 subsets, for this reason you should think harder!

In fact these are the results: apple,banana,cherry apple,banana,date apple,banana,egg apple,cherry,date apple,cherry,egg apple,date,egg banana,cherry,date banana,cherry,egg banana,date,egg cherry,date,egg

Calculating The Numbers

Is there a way of calculating the numbers such as 1, 4, 6, 4 and also 1 (instead of spring them increase in Pascal"s Triangle)?

Yes, we can discover the number of ways of selecting each number ofelements using Combinations.

There space four facets in the set, and:

The variety of ways ofselecting 0 facets from 4 = 4C0 = 1The number of ways ofselecting 1 aspect from 4 = 4C1 = 4The number of ways of choosing 2 elements from 4 = 4C2 = 6The number of ways of picking 3 facets from 4 = 4C3 = 4The number of ways of picking 4 facets from 4 = 4C4 = 1 total number ofsubsets = 16
The variety of waysofselecting 0 elements from 5 = 5C0 = 1The number of ways ofselecting 1 facet from 5 = ___________The variety of ways of picking 2 aspects from 5 = ___________The variety of ways of picking 3 aspects from 5 = ___________The variety of ways of picking 4 elements from 5 = ___________Thenumber of ways of picking 5 elements from 5 = ___________ Total number of subsets = ___________