Mathematical+Reflections,+p.+81+-+2010-2011

**JYR**
 * January 16, 2011**

=__MR 6__= **Big Ideas:** Many important practical and mathematical applications involve comparing quantities of one kind or another; it is important to know which method to use and how we should use them. **Essential Question:** __//What methods are there for comparing things?//__

MR 6

A rate is good strategy for making comparisons because you can compare which rate is greater and better because rate is easy to compare two different rates of ratios. //For example: // 4 apples for 3 dollars which is 4 apples/3 dollars and 5 apples for 5 dollar which is 5 apples/5 dollars. I will go for 4 apples and 3 dollars one because it's just 1 more apple and you have to pay 2 dollars more. That's a good thing about rates because you can see the difference because there is the same two different units in two rates.
 * 1.**
 * a. Describe a situation in which finding a rate is good strategy for making comparisons. Tell why you think your situation calls for finding a rate.**

Unit rate means comparing an amount to a single unit. So if there are two stores and one sells 5 cucumber in 10 dollars and the other one sells 6 cucumbers in 14 dollars. To make it as single you divide 5 / 10 and 6/14 and you will get 2 dollars for 1 cucumber and you get 0.42 dollars for 1 cucumber in the another store. This method helps us to find the amount of 1 thing and it's very useful and you can compare it easily.
 * b. Describe a situation in which finding a unit rate is a good strategy for making comparisons. tell why you think your situation calls for finding a unit rate.'**


 * 2. There are 17 girls and 13 boy in Mr. Baldridge's class. Write every comparison you can think about this situation and explain what each shows.**

Fraction: 17/30 girls: 13/30 boys
Percent: 57% girls : 43% boys Difference: There are 4 more girls than boys.

Rate :400 miles by 12 gallons of gas = It means that it uses 12 gallons of gas when the car drives 400 miles.
=== Unit Rate : 33.3 miles per 1 gallon of gas = It's like the same meaning as above but you divide 400 by 12 and it comes to 33.3 and 33.3 is the miles per 1 gallon of gas. ===

====**4. If you know that 4 cans of chili feed 6 people, how many cans of chili will feed 240 people? How many people can you feed with 45 cans of chili? Explain your answers. **====

For 240 people it's 160 cans because 4 cans feed 6 people. It's finding for 240 people so divide 240 by 6 = 40. So you have to multiply 40 x 4(cans) = 160. So for the 240 people one, we need 160 cans. 45 cans feed about like 67people because 4 cans feed 6 people and 45 can is almost closest to 44 cans and 44 cans feed about 66 people. 4 x 11 = 44cans. 6 x 11 = 66 people. And if it wants to be 45 cans, 1 can feed 0.6 person. I know it by 4 / 6 = 0.666. If you add them it's 66.6 = 67 people. So 45 cans feed 67 people.

5. How do you recognize a situation in which you need to use a ratio comparison rather than simply finding differences?
===I recognize a situation in which i need to use a ratio comparison rather than simply finding differences by it when there is a situation with 2 numbers and asks me to find the difference. ===

In this Investigation we learned about comparing the two rates, ratios, percents and proportions. This will help in the future when we do ratios and rates, percents etc. because we already have a knowledge about this. Through the whole unit, I learned what is ratio, rates, scale factor, percents, equivalent fraction, ratios and rates and finding the population density. This really helps me.
 * __Summary:__**

These are the some good youtube videos that will help us about rates and ratios. media type="youtube" key="EgK2JQy7144?fs=1" height="385" width="640" media type="youtube" key="167dEicyuXs?fs=1" height="385" width="480"