What roster notation? Roster notation is a mathematical way to represent the parts of a set. The elements of the set are written in between two brackets and each element is separated by a comma.
How to use roster notation:
To use roster notation, first look at the elements of a set.
For example, if you are given the set of odd numbers between 10 and 20:
the elements would be 11,13,15,17,and 19.
To write this in roster notation, put the elements between two curly brackets and place commas between each element.
This set written in roster notation will be:
{11,13,15,17,19}
This works for any given set. It does not only have to be for numbers.
For example, if you are given a set of the consonants in the alphabet, the elements of the set would be b,c,d,f,g,h,j,k,l,m,n,p,q,r,s,t,v,w,x,y,z
In roster notation, this would be written as:
{b,c,d,f,g,h,j,k,l,m,n,p,q,r,s,t,v,w,x,y,z}
Sample Math Problems
Question
Write the set of even numbers between 1 and 10 in roster notation.
Answer
In this problem we first need to find what the even numbers are between 1 and 10. They would be 2,4,6,8
In roster notation, this would be:
{2,4,6,8}
Question
You are given a set of numbers less than 20, but greater than 5 that are divisible by 3. Write this set in roster notation.
Answer
First, figure out the numbers that are less than 20, but greater than 5.
These would be 6,7,8,9,10,11,12,13,14,15,16,17,18,19.
Next, determine which numbers are divisible by 3.
This would be 6,9,12,15,18
In roster notation, the set would be written as:
{6,9,12,15,18}
Question
Sarah rolls a die 5 times. The chart below shows what she rolled on each roll. Write the set of numbers that Sarah rolled in roster notation.
Answer
Looking at the chart, we can see that Sarah rolled two 1’s, a 6, a 3 and a 4.
In roster notation, the set of numbers Sarah rolled would be:
{1,1,6,4,3}
Question
Johnny flipped two coins. Write the set of possibilities of just one coin landing on heads in roster notation.
Answer
First, write all the possible ways the two coins could land.
This would be HH,HT,TH,TT
Now choose the options that have only one coin land on heads. This would be HT or TH. The set of possibilities where one coin lands on heads written in roster notation is {HT,TH}
