Decimals

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Decimals
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Ordering Decimals

• (1)Line Up Decimal Points
• (2)Start at the left and find the first place
  where the digits differ. Compare the digits
• (1) 42.1 (2) 42.1lt42.5
• 42.5 1lt5
• Since 1 is less than 5, we know 42.1 is smaller
  than 42.5!

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Rules for Adding and Subtracting Decimals

• (1) Line up the numbers by the decimal point.
• (2) Annex zeros to make the same number of
  places behind the decimal point in all numbers in
  the problem.
• (3) Add or subtract beginning on the far right
  side of the problem.
• (4) Place the decimal point in the answer by
  bringing the decimal point straight down from the
  problem to the answer.
• the answer.

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Adding and Subtracting Decimals
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Rules for Multiplying Decimals

• (1)You do not line up the factors by the decimal.
• (2)Instead, place the number with more digits on
  top.
• (3)Multiply
• (4)Count the number of decimal places (from the
  right) in each factor.
• (5)Use the total number of decimal places in your
  two factors to place the decimal in your product.

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Multiplying Decimals
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Rules for Dividing Decimals

• (1)If the divisor is not a whole number, move
  decimal point to right to make it a whole number
  and move decimal point in dividend the same
  number of places.

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Rules for Dividing Decimals

• (2)Put decimal point directly above decimal point
  in the dividend.

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• (3)Divide as usual. Keep dividing until the
  answer terminates or repeats.