On 18/09/2010 9:08 AM, Omelet wrote:
> In article
> >,
> > wrote:
>
>>> what is idiotic about teaching there other base numbers systems apart from
>>> ten?
>>>
>>
>> It's not math you can use unless you want to be a programmer.
>>
>> I wish elementary math classes spent more time on practical
>> applications and less time on pure manipulation. (Mom and Dad want to
>> paint their bedroom. Given that their room is 10 feet by 15 feet by 8
>> feet high, how many gallons of paint do they need to buy, given that
>> one gallon of paint covers 500 square feet, and two coats will be
>> needed to cover the existing color.)
>>
>> The vast majority of students, even ones good at manipulation, will
>> find setting up this problem to be difficult.
>
> Let's see... That means that 2 walls are 8x10 and 2 walls are 8x15?
>
> That's 160 + 240 so 400 square feet.
>
> 2 cans with some left over for the two coats required...
>
> Providing you are not doing the ceiling with the same color. That'd be
> an additional 150 square feet for a total of 550 x 2 coats is 1,100.
>
> 3 cans with LOTS left over for later touch ups. Walls get damaged so
> it's not a bad idea to keep some on hand anyway. ;-)
>
> I prefer to break problems up. Makes it easier. For instance, I owed a
> friend some money this morning and needed to write her a check. Part of
> the work she'd done was $25.00 and the laundry bill was $12.00. So,
> instead of trying to add 25 and 12, I showed her to mentally add 25 + 10
> + 2. She is about 10 years or so younger than me, but she tries to
> practice this skill regularly to save money so has gotten good at it. :-)
>
> I need to drag her into a game of triple Yahtzee some time...
>
> I break down basic addition and subtraction into sets of 5 and 10, then
> add or subtract the remaining number that is less than 10.
>
> Works for me anyway!
>
> Same for multiplication. I break up the numbers into base numbers (and
> often kill the zeros temporarily), then add them back together when I am
> done.
>
> If all else fails, I drag out a pen and paper.<g>
>
> I'd personally like to see electric calculators BANNED from grade
> schools!
>
> I will resort to my cell phone calculator tho' at the grocery store when
> I need to divide odd numbers. Like to get the cents per oz. of oddly
> packaged products (14 oz. for instance instead of 16 oz. if I'm trying
> to find the difference in cost per lb.) I could do it if I wrote it
> down and did it manually, but it's more difficult for me to mentally
> divide odd numbers.
>
> Many people cannot do simple math in their heads, and that brings me to
> an on-topic rant.
>
> HEB is doing it again! Making "bulk" items more expensive than smaller
> items! Anyone should be able to at least multiply by two without using
> a calculator.
>
> 2 days ago, I was purchasing eggs. I generally get the 18 count cartons.
> They have some bulk cartons of 36 eggs. So, I multiplied the cost of the
> 18 count cartons x 2.
>
> The price for two 18 count cartons was cheaper than the bulk cartons of
> 36 eggs by 44 cents.
>
> <sigh>
>
> I then went to purchase some shredded cheese. It saves me time and it's
> so close to the same cost as block cheese per lb., the difference is not
> worth quibbling about. I store it in the freezer and use it only for
> cooking.
>
> However, purchasing two 1 lb. bags was 54 cents cheaper than purchasing
> the same shredded cheese in the 2 lb. bags!
>
> Gotta watch these stores like hawks I tell ya!

Sometimes it's preferable to purchase the two smaller bags regardless of
the way the discount goes as the unopened one will remain fresher for
longer.

Krypsis