Verified Answer :

  • Identify the tenths digit for each number to determine the rounding direction.
  • Round \(88.315\) down to \(88\) because the tenths digit is \(3 < 5\).
  • Round \(68.41\) down to \(68\) because the tenths digit is \(4 < 5\).
  • Calculate the sum of the rounded numbers: \(88 + 68 = 156\).
  • Final Answer: \(\boxed{156}\)

Explanation

  1. Understanding the Rounding Process

To estimate the sum of \(88.315\) and \(68.41\), we first round each of these numbers to the nearest whole number. The rule for rounding to the nearest whole number is to check the first digit after the decimal point (the tenths digit). If the digit is less than 5, we round down to the current whole number. If the digit is 5 or greater, we round up to the next whole number.

  1. Rounding Each Number

First, consider the number \(88.315\). The digit in the tenths place is \(3\). Since \(3 < 5\), we round down to \(88\). Next, consider the number \(68.41\). The digit in the tenths place is \(4\). Since \(4 < 5\), we round down to \(68\).

  1. Calculating the Estimated Sum

Now that we have rounded the numbers to \(88\) and \(68\), we calculate the estimated sum by adding these two integers together:
\[88 + 68 = 156.\]
Thus, the estimated sum of \(88.315 + 68.41\) is \(156\).

Examples

Rounding numbers is a common strategy used when you are shopping at a store and want to quickly estimate the total cost of items in your cart. For example, if you are buying a gallon of milk for \(\$4.25\) and a loaf of bread for \(\$3.70\), you can mentally round them to \(\$4\) and \(\$4\) respectively to estimate that your total will be around \(\$8\). This technique helps you manage your budget and make quick financial decisions without needing an exact calculation.

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