It's actually terrible, I forgot my book, and I'm stuck doing homework, and it's hard. I'm in fifth grade.
6. List all of the numbers up to 20 that can be arranged into arrays with two rows.
16, and 20, there's more but.
7. What do you call numbers listed in problem 6?
Blank.
Shelby:
20 can be represented by two factors, 4,5
16 can be represented by two factors, 8,2
What about 18? 14?
Start with four and work up, see if you can find two factors of each number.
The numbers are called factors.
Factor pairs
To find all the numbers up to 20 that can be arranged into arrays with two rows, we need to look for numbers that have factors other than 1 and themselves. In other words, we want to find numbers that can be divided into two equal groups.
To start, we can write down all the numbers from 1 to 20. Then, for each number, we can try dividing it by various factors and see if it can be arranged into two rows. For example, if a number can be divided into two equal groups of 2 and 2, then it can be arranged into an array with two rows.
Let's go through the numbers and find those that meet the criteria:
1 is not suitable because it cannot be divided into two equal groups.
2 is not suitable because it only has one factor, which is itself.
3 is not suitable because it only has one factor, which is itself.
4 can be arranged into two rows: (2, 2).
5 is not suitable because it only has one factor, which is itself.
6 can be arranged into two rows: (2, 3) or (3, 2).
7 is not suitable because it only has one factor, which is itself.
8 can be arranged into two rows: (2, 4) or (4, 2).
9 can be arranged into two rows: (3, 3).
10 can be arranged into two rows: (2, 5) or (5, 2).
11 is not suitable because it only has one factor, which is itself.
12 can be arranged into two rows: (2, 6), (3, 4), or (4, 3).
13 is not suitable because it only has one factor, which is itself.
14 can be arranged into two rows: (2, 7) or (7, 2).
15 can be arranged into two rows: (3, 5) or (5, 3).
16 can be arranged into two rows: (2, 8), (4, 4), or (8, 2).
17 is not suitable because it only has one factor, which is itself.
18 can be arranged into two rows: (2, 9), (3, 6), or (6, 3).
19 is not suitable because it only has one factor, which is itself.
20 can be arranged into two rows: (2, 10), (4, 5), or (5, 4).
So, the numbers up to 20 that can be arranged into arrays with two rows are 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, and 20.
For problem number 7, the numbers listed in problem 6 can be called "numbers that can be arranged into arrays with two rows."