1. March 18, Math 201
Objective: Students will be able to make a reasonable estimate and justify it.
Aim: How can we use our knowledge of rounding up or rounding down help make a reasonable estimate?
Standards: 6.M.8, 6.M.9
Prior Knowledge: 1) Round 436 to the nearest hundred
2) Round 94 to the nearest ten
3) Round 23.5 to the nearest one

2. Mini Lesson:
When you shoot a basketball, what happens when you aim too high? Too low?
When we make estimates for a measurement we can determine an upper bound (high estimate) and a lower bound (low estimate).
A reasonable estimate for the measurement will be between the bounds.

3. Richie carried 8 boxes into Mr. Kabinoff’s office
Richie carried 8 boxes into Mr. Kabinoff’s office. The boxes weighed between 20 and 30 pounds. What is a reasonable estimate for the amount of weight Richie carried?
Find a reasonable upper and lower bound.
Determine a “friendly” number” of packages to use. A friendly number is a number that is close to the exact number but easier to work with. Use 10
3) Find a reasonable lower bound. 10 x 20 =200 lbs
4) Find a reasonable upper bound. 10 x 30 = 300 lbs
A reasonable estimate for the amount of weight is about 250 pounds

4. Keisha’s family drank a 2 liter bottle of water every week for a year (52 weeks). Keisha estimated that her family drank about 75 liters of water for the year. Is this a reasonable estimate?
Determine a friendly number of weeks to use: 50
2) Multiply 2 liters x 50 = 100 liters
Keisha’s estimate is too low, and therefore not a reasonable estimate. A better estimate is a 100 liters.

5. Crystal has 47 DVDs in her collection
Crystal has 47 DVDs in her collection. Each DVD cost between $20 and $30. What is a reasonable estimate for the amount of money Crystal spent on her DVDs?
1) Determine a friendly number of DVDs to use.
2) Find a reasonable lower bound
3) Find a reasonable upper bound
So, a reasonable estimate would be somewhere in between, such as ________

6. A construction company has 1,463 bricks.
Each brick weighs between 3 and 4 pounds.
What is a reasonable estimate for the weight of the bricks?

7. Homework:
Paul ran 5 miles. He ran each mile between 7 and 8 minutes. About how long did it take Paul to run?