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Estimating differences

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Intros
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Lessons
  1. Example of estimating the difference of 2314 - 1598
  2. Key concepts for estimating differences and rounding review
  3. Front-end estimation for differences
  4. Estimation by rounding for differences
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Examples
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Lessons
  1. Front-End Estimation of Differences
    Estimate the difference using front-end estimation. Then, find the exact difference to check your answer.
    1. 7853 - 794 =
    2. 0.665 - 0.018 =
    3. 2838\frac{3}{8} - 5510\frac{5}{10} =
  2. Estimating Differences by Rounding
    Estimate the difference using estimation by rounding. Then, find the exact difference to check your answer.
    1. 9876 - 714 =
    2. 5329 - 5276 =
    3. 4.41 - 0.589 =
    4. 69.372 - 67.981 =
    5. 1723\frac{2}{3} - 959\frac{5}{9} =
    6. 5316\frac{1}{6} - 3224\frac{2}{4} =
  3. Estimating Differences Word Problem - 1
    Rachel has 152.6 cm (length) of wrapping paper, but she only needs 18.934 cm to wrap a small gift box. About how much wrapping paper will she have left over?
  4. Estimating Differences Word Problem - 2
    Stevie bought a new activity tracker. His goal is to walk 21,000 steps each week. His activity tracker shows his steps from Monday to Thursday so far:

    • Monday: 4,152 steps
    • Tuesday: 3,607 steps
    • Wednesday: 2,892 steps
    • Thursday: 4,368 steps

    About how many more steps does he have to walk for the rest of the week to reach his goal?
    1. Using front-end estimation, about how many steps has he walked already? Then, how many more steps does he need to walk to reach his goal?
    2. Using estimation by rounding, about how many steps has he walked already? Then, how many more steps does he need to walk to reach his goal?
    3. Calculate the exact number of steps Stevie still has to walk to reach his goal.
    4. Using only subtraction, estimate how many more steps Stevie needs to walk with both front-end and rounding estimation methods.
  5. Estimating Differences Multiple Choice
    Estimate the difference using multiple estimation methods. Then choose the best answer:

    21111\frac{1}{11} - 1378\frac{7}{8} =

    A. Less than 7
    B. Between 7 and 8
    C. Greater than 8
  6. Estimating Differences Word Problem - 2
    Use different estimation methods to estimate the difference. Which method gave a more accurate estimate and why?

    829\frac{2}{9} - 712\frac{1}{2} =