Friendly numbers are a special type of number that have a unique connection with other numbers. To understand this relationship, we will add up all of the factors of a number and then we look at the index of a number and compare it to the index of another number. Check it out in this mini spark.
Spark your math thinking!
1. Set up your math mini spark recording page: #102: Friendly Numbers
2. Read this paragraph to review what “Factors” are.
Factors are numbers you multiply together to get another number. A factor of a number divides the number evenly, with no remainder.
What are all the factors of the number 8? 1 2 4 8
What are all the factors of the number 24? 1 2 3 4 6 8 12 24
Write the factors of the number 40 on your recording sheet.
3. Scroll down to the bottom of this page to see if you have the correct numbers for step 2. If you do put a star on your page. If you do not, add the correct numbers.
4. Look over these 6 questions before your start watching the video. Number your paper from 1-6. As you watch answer each of the questions.
- Stop the video at 2:57. In two sentences, describe how 12 and 234 and are friendly numbers.
- How many perfect numbers are there. How has this number changed since 2011?
- What is is called if you don’t have a friend? Name a few of these types of numbers.
- Pause the video at 8:40 and write down all of the friendly numbers on his chart.
- What are the yellow numbers?
- What is 10’s index?
5. Share your math mini spark recording page with your teacher/EY coordinator
Answers for step 3
Factors of 40 are 1, 2, 4, 5, 8, 10, 20, 40