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September 17, 2013 2.4 Addition and Subtraction Number Stories

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Math Message Please complete the following problem in your Math notebook: 1) Niko has $8.00. Does he have enough money to buy 3 fancy pencils for $1.98 each and an eraser for $1.73? Yes or No? 2) Refer to SRB pg. 227- Which diagram would you use to model the situation in your Math Message? 3) What is the total cost of 3 pencils and 1 eraser?

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Lets focus on number sentences Number sentences are similar to language sentences except math symbols are used instead of words. Example: 3 x 1.98 + 1.73 = 7.67 Some number sentences are true and some are false. Such as 10 2 = 8 true number sentence 8 / 2 > 4 x 100 false number sentence

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What are open number sentences? A number sentence must have: 1) a relation symbol ( =, ) 2) contain numbers (0, 1, 2, 3, 4) 3) operation symbols (+, -, /, x) Open number sentences are neither true nor false. Only when we replace the variable with a number do we get a number sentence that is true or false. Example: 3 * 1.98 = p

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Try this! (in class) Maria had 2 decks of cards. One of the decks had only 36 cards instead of 52. The rest were missing from the deck. How many cards were missing? 1) List the numbers needed to solve the problem. 36 and 52 2) Describe what you want to find. The number of missing cards 3) Write an open sentence. 36 + c = 52 4) Find the missing number in the open sentence. Solution: c = 16 5) Write the answer to the number story. Answer= 16 cards

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September 18, 2013 2.5 Estimate Your Reaction Time

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Reviewing Mean/ Average 1) Click on the following link to review how to find mean (also known as the average) http://studyjams.scholastic.com/studyjams/jams/math/data- analysis/mean-average.htm 2) Click on step by step 3) Click on home and watch the clip 3) Click on watch- out! and watch the clip 4) Finally, click on try it! and complete the first problem in your Math notebook

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Rounding to the nearest Lets review how to round to the nearest place value Example: Rounding to the nearest tenth Use the hundredths digit to round to the nearest tenth Remember! If the hundredths digit is 4 or less, round down 0.542 0.5 0.431538 0.4 Remember! If the hundredths digit is 5 or more, round up 0.45 0.5 0.551674 0.6

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Reviewing Landmarks Maximum- the largest number in a set of data Minimum- the smallest number in a set of data Range- subtract the highest number( maximum) from the lowest number (minimum) Mode- the most frequent number (you will see it more than once) Median- after ordering your numbers, the number found in the middle (suggestion: cross off each number from both the beginning and end until you reach the middle number) Mean- add up all of your numbers to find the sum and then divide by how many numbers you had to begin with

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September 19, 2013 2.6 Chance Events

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Finding Probability 1) Click on the following link to review how to find mean (also known as the average) http://studyjams.scholastic.com/studyjams/jams/math/probability /find-probability.htm 2) Before clicking on step-by-step, define the following terms in your Math notebook: probability, equally likely, impossible, and certain 3) Click on step by step 2) Click on home and watch the clip 3) Click on watch- out! and watch the clip 4) Finally, click on try it! and practice the problem

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September 23, 2013 2.7 Estimating Products

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Math Message Complete the following problem in your Math Notebook: 1) Use the numbers 10,6,9,8, and 5 to make expressions that are equivalent names for either 1, 10, or 100. (Use addition, subtraction, multiplication, division, or exponents, and try to use all 5 numbers.) 1 Example: 5 2 10 + 9 / 8 + 3 / 6 = 1 10 100

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Magnitude Estimate A magnitude estimate is a rough estimate. It tells whether the exact answer falls in the tenths, ones, tens, hundreds, thousands, etc. 1) Round both factors to the nearest multiple of a power of 10 2) Then find the product of the rounded numbers Example: 1.83 + 2.93 = ? Number model: 2 + 3 = 5 0.1s 1s 10s 100s 1,000s

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Lets practice Is the result of 14 x 17 in the Tens? Hundreds? Thousands? The product of 14 x 17 must be greater than 10 x 10 = 100. It must be less than 20 x 20= 400. So the product is in the hundreds.