SEARCH HOME
Math CentralQuandaries & Queries

search

Question from Laura, a parent:

On a math test Grace needs to look at an array and write a division sentence for the array. Grace writes 18/3=6 on her answer sheet. Describe what the array on Graces test looks like.

Hi Laura,

I'm going to change the problem slightly.

On a math test Larry needs to look at an array and write a division sentence for the array. Larry writes 15/5 = 3 on his answer sheet. Describe what the array on Larry test looks like.

I would rewrite Larry's division sentence as a multiplication sentence. That is I would rewrite 15/5 = 3 as 5 × 3 = 15 or perhaps 3 × 5 = 15. I can draw arrays for these sentences,

dit dit dit
dit dit dit
dit dit dit
dit dit dit
dit dit dit
and
dit dit dit dit dit
dit dit dit dit dit
dit dit dit dit dit

The first is a 5 by 3 array and the second is a 3 by 5 array. (Mathematicians always write the number of rows first and the number of columns second.) Thus my response to the question about Larry's array would be to say it is either a 5 by 3 array or a 3 by 5 array.

I hope this helps,
Penny

About Math Central
 

 


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.
Quandaries & Queries page Home page University of Regina PIMS