Estimating is a guess that should be close to the answer. Round is rounding a number up to the nearest ten, hundred. Example $345.89 round to the nearest dollar is $345.
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Rounding is going to the nearest tens, hundreds, thousands etc., depending on the problem. Compatible numbers are numbers the work well with each other. Both of these are estimating.
by rounding 624 down to 600, you know that 600 divided by 6 is 100, so the first digit will probably be a 1
Estimating sumsUse rounded numbers to estimate sums.Example 1Give an estimate for the sum of 19.61 and 5.07 by rounding to the nearest tenth.Round each number to the nearest tenth.Example 2Estimate the sum of 19.61 + 5.07 by rounding to the nearest whole number.Round each number to a whole number.Estimating differencesUse rounded numbers to estimate differences.Example 3Give an estimate for the difference of 12.356 - 5.281 by rounding to the nearest whole number.Round each number to the nearest whole number.Now subtract.So 12.356 - 5.281 ≈ 7.Estimating productsUse rounded numbers to estimate products.Example 4Estimate the product of 4.7 × 5.9 by rounding to the nearest whole number.Round each number to a whole number.So 4.7 × 5.9 ≈ 30.Again, in decimals, as in whole numbers, if both multipliers end in .5, or are halfway numbers, rounding one number up and one number down will give you a better estimate of the product.Example 5Estimate the product of 7.5 × 8.5 by rounding to the nearest whole number.You can also round the first number down and the second number up and get this estimate.In either case, your approximation will be closer than it would be if you rounded both numbers up, which is the standard rule.Estimating quotientsUse rounded numbers to estimate quotients.Example 6Estimate the quotient of 27.49 ÷ 3.12 by rounding to the nearest whole number.Round each number to the nearest whole number.
Rounding is a way of simplify an exact number to make it easier to understand or remember. For example, the population of a city might be 71,212. To nearest thousand, this number is 71,000 which may be close enough for your purposes. To nearest hundred, it is 71,200 which is more accurate. Estimating is educated guessing, based on experience, visual observations, or rough calculations or other information. I might estimate the population of a city by driving around in it, counting the houses, studying a city map , aerial photograph or telephone directory or considering other information.
It depends on what you are rounding by. If you are rounding by ten-thousands=80000 If you are rounding by thousands=85000 If you are rounding by hundreds=84700 If you are rounding by tens=84650