Decimals

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Decimals
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Starter

• Complete the assignment that was given to you at
  the beginning of class. You have 5 minutes to
  complete this assignment.

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K-W-L

• Under the column labeled K tell me what you
  know about decimals.

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K-W-L

• Under the column labeled W tell me what you
  want to know about decimals.

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Worlds Longest Subway Systems
City Length (km)
London 4.15
Moscow 3.4
New York City 3.71
Seoul 2.78
Tokyo 2.81
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Comparing Decimals

• Comparing decimals is similar to comparing whole
  numbers. You use the symbols gt or lt to write an
  inequality. An inequality is a mathematical
  sentence indicating that two quantities are not
  equal.

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• Example 1
• Use lt or gt to compare Tokyos subway length
  with Seouls.

City Length (km)
London 4.15
Moscow 3.4
New York City 3.71
Seoul 2.78
Tokyo 2.81
8

• Use the place value.
• Tokyo 2.81
• Seoul 2.78

First, line up the decimal points.
Then, starting at the left, find the first place
the digits differ. Compare the digits.
Since 8gt7, 2.81 gt 2.78. Tokyo has a longer
subway than Seoul.
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• Check your progress
• Compare New York Citys subway length with
  Moscows.

City Length (km)
London 4.15
Moscow 3.4
New York City 3.71
Seoul 2.78
Tokyo 2.81
10
Ordering Decimals

• Decimals that name the same number are called
  equivalent decimals. Examples are 0.8 and 0.80.
• When you annex, or place zeros to the right of
  the last digit in a decimal, the value does not
  change. Annexing zeros is useful when ordering a
  group of decimals.

• Example 1
• Order 15, 14.95, 15.8, and 15.01 from least to
  greatest.