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DECIMALS

DECIMALS. Objectives: Read, write, and compare rational numbers Add, subtract, multiply, and divide rational numbers (integers & decimals) Compare and order decimal numbers and integers. DECIMALS. Objectives: Analyze word problems Solve real life problems involving decimals and integers.

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DECIMALS

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  1. DECIMALS Objectives: • Read, write, and compare rational numbers • Add, subtract, multiply, and divide rational numbers (integers & decimals) • Compare and order decimal numbers and integers

  2. DECIMALS Objectives: • Analyze word problems • Solve real life problems involving decimals and integers

  3. DECIMALS Activities: • Independent Work • Pair Work • Small Group Activities • Puzzles & Games

  4. DAY 4: Comparing and Ordering Decimals

  5. Ordering decimals • Can you arrange the following prices from cheapest to the most expensive?

  6. McDonald’s Menu….I’m Lovin It!! • Double Cheeseburger: $ 0.99 • Big Mac Value Meal: $ 4.79 • Chicken McNuggetts Meal: $ 3.80 • Small Drink: $ 0.99 • McFlurry: $ 1.97 • Salad: $ 4.80 • 2 Cheeseburger Meal: $ 3.70 • Ice Cream Cone: $ 0.87

  7. Order Up!Least Expensive to Most Expensive • Ice Cream Cone .87 • Double Cheeseburger: .99 • Small Soft Drink: .99 • McFlurry: 1.97 • 2 Cheeseburger Meal: 3.70 • Chicken McNuggetts Meal: 3.80 • Big Mac Value Meal: 4.79 • Chicken Salad: 4.80

  8. What Does It Mean to Compare Decimals? • When we compare we use terms such as: • Less than < • Greater than > • Equal to = • Comparing decimals is similar to comparing whole numbers. • 45 < 47 45 is less than 47 • 150 > 105

  9. Place Value Hundreds Ones Thousands Tens Tenths Hundredths Thousandths Ten-thousandths

  10. Half pipe Scores Who scored the highest? • Check at the numbers on the left of the decimal point. These are the whole numbers. Which one is the greatest? • If there are more than two of these numbers, check the decimal places. • In this case, it is obvious that Jacob scored the highest, the score being 46.1. • Then we have Sara, Danny and Ross at 42. • 42.1 • 42.5 • 42.0 • Compare the number after the decimal point and order from least to greatest

  11. Let’s Try Using A Number Line 42 40.7 46.1 42.0 42.1 42.5 Since numbers to the right are greater than numbers, then we can say that the winner is Jacob (46.1), Danny (42.5), Sarah (42.1), Ross (42.0) and Bethany (40.7)

  12. Equivalent Decimals • Decimals that name the same number are called equivalent decimals. • 0.60 and 0.6 • Are these the same???

  13. = 0.60 0.6

  14. Annexing Zeros • This means placing a zero to the right of the last digit in a decimal. • 0.6 0.60 • Although we added a zero, the value of the decimal did not change!! • Annexing or adding zeros is useful when ordering a group of decimals.

  15. Ordering Decimals • We can order decimals from least to greatest or we can order from greatest to least. • Let’s try an example: • Order 15, 14.95, 15.8, and 15.01 from least to greatest

  16. 15, 14.95, 15.8, 15.01 • LEAST TO GREATEST • First, line up the decimal points 15 14.95 15.8 15.01

  17. 15, 14.95, 15.8, 15.01 • Next, annex zeros so that each number has the same number of decimal places 15.00 14.95 15.80 15.01

  18. 15, 14.95, 15.8, 15.01 • Finally, use place value to compare the decimals. Always start from the left!! 15.00 14.95 15.80 15.01 • 14.95, 15, 15.01, 15.8

  19. One More Example Order these numbers from greatest to least • 35.06, 35.7, 35.5, 35.849 • Did you write- • 35.849 • 35.700 • 35.500 • 35.060

  20. TEAMMATES CONSULT • Answer the following: • Arrange the numbers from greatest to least 0.808, 0.080, 0.80, 0.888

  21. Teammates Consult • Answer the following: • The five car racers obtained the following time: Who reached the finish line 1st, 2nd, 3rd, 4th and last? • BMW: 4.2 • Corvette: 4.16 • Ferrari: 4.25 • Porche: 4.03 • Mercedes: 4.22

  22. Teammates Consult • Answer the following: • The preschool children took care of some rabbits in their classroom. They fed each one daily. At the end of two weeks, the six rabbits weighed: 7.15; 7.02; 7.25; 7; 7.05; 7.02. • Arrange the weights in order from least to greatest.

  23. Optional • http://www.mathsisfun.com/numbers/decimals-dividing-animation.html

  24. Day 6: Multiplication of Decimals

  25. Multiplication of Decimals • Remember: • Multiplication is REPEATED ADDITION • So, if you have: 4 x 3.5, this means- • 3.5 + 3.5 + 3.5 + 3.5

  26. Multiplication of Decimals • 3.5 + 3.5 + 3.5 + 3.5 can be written as 3.5 3.5 +3.5 3.5 14.0

  27. Multiplication of Decimals • Try these! • 1.2 x 6 = • 5 x 3.2 =

  28. Multiplication of Decimals • Did you re-write the problems vertically? 1.2 x 6 7.2

  29. Multiplication of Decimals • 5 x 3.2 = 3.2 X 5 16.0

  30. Multiplication of Decimals • What should be done when both factors have decimal numbers? • Example: 3.2 x 1.4 =

  31. Multiplication of Decimals 3.2 x 0.4 = • Re-write the equation: 3.2 X 0.4

  32. 3.2 X 0.4 • Multiply the digits as if they were whole numbers • Look at the problem and count the digits after the decimal point. 3.2 x 0.4 12 8 + 12 0 3.2 x 0.4 24 8 2.48

  33. Try These!

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