Estimating Differences

Did you know it’s possible too to utilize rounding for estimating differences? At times whenever you do subtract between two large numbers, you do not wish to find out the precise differences. You only wish to know a fast estimate. It’s possible to get an estimate by rounding each of the numbers, then discovering a difference that’s near the precise difference.

Related Topics

• Estimating and Rounding
• Estimating Products
• Rounding Numbers

Way to estimate Differences to the closest tenth

Here is a fast review of the rules for rounding numbers.

STEP one: If the number one puts on the right of the targeted number was lower than \(5\), it gets rounded down ?

STEP two: If the number one position to the right of the targeted number is \(5\) or higher, it gets rounded up ?

STEP three: Now it is possible to get the difference in-between these rounded numbers. Whenever the minuend and subtrahend in a subtraction equation are rounded, the subtraction gets easier.

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Note: You merely must remember to maintain the difference near the precise answer

 Tip one: Unless it says something different, constantly round figures to the maximum feasible place value.

Tip two: You should pay attention to the fact we constantly write down the word “about” before the estimated difference. That shows you the result isn’t the precise answer, merely the estimate.

Estimating Differences – Example 1:

Estimate differences by rounding each added to the nearest ten.

\(85-34=\)___

Solution:

First, round \(85\) to the closest ten. Check out the numeral on the right of the tens position. It is \(5\). So, \(85\) is rounded up to \(90\). Do the same for \(34\). Then \(34\) is rounded down to \(30\). Now subtract \(30\) from \(90\): \(90-30=60\)

Estimating Differences – Example 2:

Estimate differences by rounding each added to the nearest ten.

\(53-26=\)___

Solution:

First, round \(53\) to the closest ten. Check out the numeral on the right of the tens position. It is \(3\) and this number is lower than \(5\). So, \(53\) is rounded down to \(50\). Do the same for \(26\). Then \(26\) is rounded up to \(30\). Now subtract \(30\) from \(50\): \(50-30=20\)

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Exercises for Estimating Differences

Estimate differences by rounding each added to the nearest ten.

1. \(\color{blue}{77-23}\)
2. \(\color{blue}{ 94-48 }\)
3. \(\color{blue}{35-12 }\)
4. \(\color{blue}{ 62-53 }\)

1. \(\color{blue}{60}\)
2. \(\color{blue}{ 40 }\)
3. \(\color{blue}{30 }\)
4. \(\color{blue}{ 10 }\)