- There are 15 cars in Michael's matchbox car collection. Two-thirds of the cars are red. How many red cars does he have?
Unit Parts Without Subdivisions
- You have 3/4 of a pizza left. If you give 1/3 of the leftover pizza to your brother, how much of a whole pizza will your brother get?
- Someone ate 1/10 of the loaf of bread, leaving 9/10. If you use 2/3 of what is left to make French toast how much of a whole loaf have your used?
- Gloria used 2 1/2 tubes of blue paint to paint the sky in her picture. Each tube holds 4/5 ounce of paint. How many ounces of blue paint did Gloria use?
Subdividing the Unit Parts
- Zack had 2/3 of the lawn left to cut. After lunch, he cut 3/4 of the grass he had left. How much of the whole lawn did Zack cut after lunch?
- The zookeeper had a huge bottle of the animals' favorite liquid treat, Zoo Cola. The monkey drank 1/5 of the bottle. The zebra drank 2/3 of what was left. How much of the bottle did the zebra drink?
Role of Estimation
Predict with will happen. Rounding a tool that can be used to help estimate, but rounding isn't estimating. Rounding is the process to help estimate.
If students understand benchmark fractions, that will help them when it comes to estimating.
- Addition
- 3/4 + 7/5 .....7/5 is more than a whole, 3/4 is almost a whole. I can estimate that my answer will be more than a whole. (Benchmark close to 1)
- Subtraction
- The same as addition, or at least pretty darn close.
- Multiplication
- In fractions there is an influction point, it is 1.
- Alice in Wonderland Fractions
- How Tall is Alice
- 1st number in multiplication is our starting part. The second number is doing the work. We compare to where we start to where we end. If I am multiplying by something greater than one, then my answer will be greater than my starting point. If I multiply by something smaller than one, my answer will be smaller than my starting number.
- 4/5 x 4/9 = the answer will be less than 4/5 because 4/9 is less than 4/5. The answer is a lot smaller than 4/5.
- 4/5 x 1/15 = 1/15 is smaller than 4/5, the answer to this question will be smaller than the answer for 4/5 x 4/9.
- When asking kids to estimate, you don't want an answer, you want AN ESTIMATION
- Division
- a divided by 5 = a x 1/b
- 12 divided by 3 = 12 x 1/3
- When dividing fractions, you are multiplying by the reciprocal
- Multiplication rules apply for division when estimating
- Models for Dividing Fractions
Where Does the Decimal Go? (pg. 343 Van de Wall)
- 24 x 63 = 1512
- 0.24 x 6.3 = 1.512, the decimal goes between the 1 and the 5 because the number one thousandths smaller (compare to the problem w/out decimals)
- 24 x 0.63 = this answer is one hundreths smaller so the answer is 15.12
- 2.4 x 63 = this answer is one tenths smaller so the answer is 151.2
- 0.24 x 0.63 = this answer is one ten thousandths smaller so the answer is .1512
The key to decimals is understanding the base 10 system.
Homework
- Journal Entry
- Beckman pg 206-207 1, 3, 6
- Reading (Parker) 150 - 154
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