3rd grade question

Question

10 oatmeal packs cost $2.00

how much is one pack. What is the best way to explain if a student does not know division.

 

thank you

Answer 1

First, the student MUST understand that $2.00 is 200 pennies.

 

Option I:

    Use multiplication.  What number when multiplied by 10 gives 200?

    Recall the rule that when multiplying by 10, just add a zero to the

    number by which you are multiplying. With that said, what number

    will result in 200 when multiplied by 10? Why 20, of course!

 

 

Option 2:

   Use repetitive subtraction....

 

    200 - 10 = 190

    190 - 10 = 180

    180 - 10 = 170

    170 - 10 = 160

    .... etc etc etc.

    30 - 10 = 20

    20 - 10 = 10

    10 - 10 = 0  

 

  So how many times has 10 been subtracted until the remainder is zero?

  20 times of course.

 

 

Absolute Last Resort:

 

      get 200 pennies and have the student put them in piles of 10.

      Then count how many piles of 10 there are. Of course there will be 20

      of them. So each pile is 20 cents. Therefore each oatmeal pack costs 20 cents

 

 

There are other options, but these rely on strong mathematical

concepts that division is multiplication in reverse and repetitive subtraction.

The last resort option is kinesthetic and tactile in nature which is beneficial

to many students. Use them combination if you must to convince the student.