Use the additive inverse to find −492.89−(−871.78)

1 answer

To find \(-492.89 - (-871.78)\), we can use the property of the additive inverse. When subtracting a negative number, it's equivalent to adding its positive counterpart.

Thus,

\[ -492.89 - (-871.78) = -492.89 + 871.78 \]

Now, we can perform the addition:

  1. Add the absolute values: \[ 871.78 - 492.89 \]

  2. Align the numbers for addition: \[ \begin{array}{r} 871.78 \ -492.89 \ \hline \end{array} \]

  3. Subtract the values:

    • Start from the rightmost digit:
      • \(8 - 9\): we need to borrow, making it 18 - 9 = 9 (we borrow 1 from 7, changing it to 6)
      • \(6 - 8 = -2\), so we borrow again, making it 16 - 8 = 8 (now 6 becomes 5)
      • \(5 - 2 = 3\)
      • Now we have \(8 - 4 = 4\)
      • Lastly, \(8 - 0 = 8\)

So,

\[ 871.78 - 492.89 = 378.89 \]

Therefore,

\[ -492.89 - (-871.78) = 378.89 \]

The final result is:

\[ \boxed{378.89} \]