Question

In the following exercise, simplify each expressions.

$-\left(4-5\right)-\left(7-8\right)$

Short answer

The simplified value is 2.

Step-by-step solution

Step 1. Concept Used.

According to subtraction property, the subtraction of a number is equal to the addition of its opposite. This can be expressed as follows.

$a-b=a+\left(-b\right)$

Step 2. Simplification inside parentheses.

Add the opposite of 5 with 4 inside the first parentheses and opposite of 8 with 7 in the second parentheses.

$-\left(4-5\right)-\left(7-8\right)=-\left(-1\right)-\left(-1\right)$

Step 3. Calculation.

Add the opposite of the opposite of 1 with the opposite of the opposite of 1.

$\begin{array}{rcl}-\left(-1\right)-\left(-1\right)& =& 1+1\\ & =& 2\end{array}$

Step 4. Conclusion.

The simplified value of the given expression is 2.