Money and Rounding

  I've noticed that students in this location have  tremendous difficulty in rounding money when shopping or deciding when the value should be rounded up or down.

I've noticed many people who shop at the local store tend to just grab food, watch the total as its all being rung up and if it goes over a certain amount, they add and take off food until the total matches the amount they can spend.

Most of my students do not know they should round the prices to make it easier to determine the total amount they are spending at the store.

So I send students to the store with a list of products they need to find the prices of.  I use this to put together an activity that requires them to round the prices so they can estimate how much they might spend.  Unfortunately, when they round anything, they carry out the math first and then round the answer.

I've also taken time to discuss why you might round something up or down, depending on who you are.  For instance, if you are a tax collector, you might round a taxpayer's amount up so you get a bit more but if you are paying money to someone, you might round it down so you pay less.  When I brought that up, the kids looked at me strangely because they've only been told the usual rule of 4 or under round down or 5 and above, round up.

I actually took time to show how if $32.5447 is rounded up to $32.55 when collecting it.  The $.0053 adds up to quite a bit of money when you are talking 100,000 people.  On the other hand, by rounding it down to $32.54 when paying someone money.  I showed they could save quite a bit if they had to pay 100,000 people. 

This is not a topic covered in elementary or middle school math.  I wish they'd take time to talk about it so students are exposed to it.  Sometimes, I think nuances are left out when teaching mathematics.  I don't know if they teach rounding of money in real life situations or are the situations contrived.

I try to provide real life situations and experiences for my students so they learn more because some of the situations are not as obvious living in the wilds of Alaska.

As usual let me know what you think.  Have a great day.