Dividing Mixed numbers

Question

A recipe for onion soup calls for 1 1/4 cups of onions.  Amy has 5 cups of onions.

 

Model with matematics.  Draw a model you can use to find the number of batches of soup Amy can make. 

Answer 1

You can do this in the following NEAT way.

 

Since you have to divide 5 by 1¼, you can UPSCALE each number, converting it to an integer divided by another integer. In this case, multiplication by 4 is required to get the one fourth into a whole.

 

So 5 ÷ 1¼ equals 20 ÷ 5 since four times 1¼ is 4+1, or five. Therefore the quotient is FOUR batches of soup (Answer).

 

It seems unlikely that this method would be the first to occur to your teacher.  Therefore this is a true learning opportunity, and is a valid topic for critical thinking--so that is to be encouraged.

 

I invite you to discuss this answer with your parents before taking it into class. Report back to me everyone's reaction, please, if you can.

 

Of course, you could always do this problem using decimal division, if you would prefer.  Or even by successive subtractions!!