Wednesday, July 16, 2008

Day three of the Singapore Math conference

My brain feels like it is about to explode!

Three days of math, and I am on math over load. I still say that if they had taught these skills this way when I was in school, we could have taken over the world.

Its a giant conspiracy project!! LOL

I promised yesterday to give more examples today, so here we go! (PS anyone know where I can get something to make blocks on the page? Hummm...)

Ratios, who in their right mind, has been able to just do ratio problems? All of you math geeks need not answer that question!!! Until this week, I am telling you this required a great deal of thought on my part and lots and lots of stress. Even after teaching it online the last two years I have struggled with how to do ratio problems. It was just something that I could not wrap my mind around. After this week, all of that stress is in the past!

Here's what I mean!

The ratio of pancakes orders to waffle orders, to egg orders is 4:2:1. If the eggs were ordered 13 times, how many times were the waffles ordered?

First things first, read the problem sentence by sentence underlining the who and what

The ratio of pancakes orders to waffle orders, to egg orders is 4:2:1. If the eggs were ordered 13 times, how many times were the waffles ordered?

Step two: List the varibles:
Pancake orders:

Waffle orders:

Egg orders:

Step three: draw a unit bar to model each varible, make these all the same size
Pancake orders:[ ][ ][ ][ ]

Waffle orders:[ ][ ]

Egg orders:[ ]

Step four: determine what each unit bar represents and where you need to place a question mark.
In this problem we know that there are 13 egg orders, so each [] represents 13, we need to know how many waffle orders there are so we will place the question mark at the end of the waffle orders.
Pancake orders:[ ][ ][ ][ ]

Waffle orders:[ ][ ] ? [ ] = 13

Egg orders:[13]

Step five: compute the problemIn this problem we would now multiply 13 by 2 giving us an answer of 26.

Step six: Answer the problem in complete sentences to ensure that you understood the question.

Waffles were ordered 26 times.


Here let me show you a different one, that isn't quite as straight forward.

There were 150 animals on the farm. The ratio of horses to cows is 3 to 2. How many horses are there? How many cows are there?

First things first, read the problem sentence by sentence underlining the who and what

There were 150 animals on the farm. The ratio of horses to cows is 3 to 2. How many horses are there? How many cows are there?

Step two: List the varibles:

Horses

Cows

Step three: draw a unit bar to model each varible, make these all the same size
Horses [ ] [ ] [ ]
=150
Cows [ ] [ ]

Step four: determine what each unit bar represents and where you need to place a question mark.
In this problem we know that we have a total of 150 animals, so to determine the number that each [ ] stands for we need to divide 150 by the number of [ ], so we need to divide 150 by 5, which equals 30, so each [ ] stands for 30 animals.

Horses [30] [30] [30]
=150
Cows [30] [30]

Step five: compute the problem
In this problem we would now multiply 30 by 3 for 90 horses, and 30 by 2 for 60 cows

Step six: Answer the problem in complete sentences to ensure that you understood the question.
There are 90 horses, and 60 cows on the farm.

This is just one example of the processes that I learned over the last 3 days. I am going to try and share a different example a day for a few days. Even if no one else gets anything out of it, it helps me get it through my thick skull.
Post a Comment