How many prime numbers are there between 1 and 100?
Go to http://studyjams.scholastic.com/studyjams/jams/math/multiplicationdivision/prime-composite-numbers.htm . You will need to have the volume turned
on to hear the tutorial. Then click “step by step” to get started. You will need to
click NEXT or SHOW ME to move through the tutorial. If you miss something that
is said, click the arrow inside the red circle to replay the information.
After watching the tutorial, use a hundreds chart to write the numbers from 1 to
100 NEATLY. Each person should do this. You will need it tomorrow. On the lines
under the hundreds chart, write the definition of prime in your own words.
The number one is not prime or composite because it only has one factor: 1.
One the hundreds chart, you need to circle numbers that are prime and put an X
on the composite numbers. How many prime numbers are there between 1 and
100? See Mrs. Caton to find out if your answer is correct before moving on!
What is a factor tree?
A factor tree is also known as prime factorization. Discuss with
your partner what you think prime factorization might be based on
the words prime and factorization. Watch the tutorial at
http://studyjams.scholastic.com/studyjams/jams/math/multiplicationdivision/prime-factorization.htm . Click “step by step” to get started. You will need
to click NEXT or SHOW ME to move through the tutorial.
Discuss what prime factorization is according to the video. Discuss how the real
definition of prime factorization compares to your guess.
Choose a composite number from your hundreds chart. Write that number at the
top of one of the trees. Make a factor tree for your number. Write your prime
factorization at the bottom of the tree. Each person should make a 3 factor trees.
Be sure to check each other and don’t pick the same numbers.
110
11
10
2
5
2 x 5 x 11 = 110