What do you call the numbers that cannot be arranged into 2-row arrays?

Thanks,
Liz & Samantha

 


Hi Liz and Samantha,

If I have a bag of lollipops and I want to divide them all between the two of you than I can organize the lollipops in two rows, one for Liz and the other for Samantha. If I can do it so that you each gets the same number of lollipops then the number I had in the bag must have been even. If I can't organize them into a 2-row array with the same number in each row then the number of lollipops must have been odd.

Penny

Liz and Samantha wrote back.

I am in 5th grade & was not sure about this...
If you call the numbers that cannot be arranged into 2-row arrays, Odd Numbers, would you call the numbers that can be arranged into 2-row
arrays, Even Numbers?
Would I have been wrong if I called them "Products"?

This was the third question in our homework. The one before it was a group of numbers, we had to take out the ones that could be put into 2-row arrays.
The question before that was multiplication questions that you had to put the answers into the 2-row arrays They were all the even numbers...
Therefore, Samantha said that they were "Products", when the teacher may not have been connecting all of the questions & just was looking for "Even Numbers"...
What do you think...
Thanks so much.
Liz & Samantha

Hi again,

You are correct when you say "the numbers that can be arranged into 2-row
arrays are even numbers". To call them products however is erroneous. the number 15 is a product, 15 = 3 x 5 but 15 is odd not even. In fact

  • the product of two even number is even

  • the product of an even number and an odd number is even

  • the product of an odd number and an even number is even, but

  • the product of two odd numbers is odd.

What you can say is that a number is even if it can be written of the product of two numbers, one of which is 2. Thus, for example

  • 6 is even since 6 = 2 x 3

  • 4 is even since 4 = 2 x 2

  • 2 is even since 2 = 2 x 1

but 9 is not even since you can't write 9 as 2 times another integer.

Penny