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The Lumenary
Darasa la 3–5AnalysisImepangwa

Estimation and rounding

Rounding to the nearest ten, hundred or tenth, estimating sums and products, and judging how far an estimate might be from the exact answer.

math.analysis.estimation

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Whole-number arithmetic

Masharti ya awali ya lazima 4 (hadi chini kabisa)

Utajifunza

  • Round whole numbers and decimals to a given place, and explain the convention for halfway cases.
  • Estimate sums, differences and products before calculating, and use estimates to check answers.
  • Give lower and upper bounds for a quantity, such as 'between 300 and 400'.

Fasili

  • Rounding replaces a number by a nearby simpler number, such as the nearest multiple of 10.
  • An estimate is an approximate value; its error is the difference between the estimate and the exact value.
  • A lower bound and an upper bound are numbers known to be at most and at least the quantity.

Nadharia

  • Rounding a whole number to the nearest ten changes it by at most 5.
  • If 30 ≤ a ≤ 40 and 20 ≤ b ≤ 30, then 50 ≤ a + b ≤ 70.
  • Rounding errors can accumulate: rounding many numbers before adding can be further off than rounding the total once.

Mawazo potofu ya kawaida

  • Thinking an estimate is a wild guess rather than a reasoned approximation.
  • Believing that rounding at every step of a calculation never changes the final rounded answer.

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