Question

Find each sum or difference.

$18.4-\left(-3.2\right)$

Short answer

The value of the expression is 21.6.

Step-by-step solution

Step 1. Concept of addition and subtraction.

Two numbers with similar signs get added and the resulting number carries the similar sign.

Two numbers with opposite signs get subtracted and the resulting number carries the sign of the larger number.

Step 2. Apply the concept of like and unlike signs.

If there is a sign like $+\left(+\right)$or$-\left(-\right)$ then the resulting sign will be positive and if there is an unlike sign $+\left(-\right)$or $-\left(+\right)$then the resulting will be negative.

So, using these rules, the given expression can be written as.

$\begin{array}{l}=18.4-\left(-3.2\right)\\ =18.4+3.2\end{array}$

Step 3. Evaluate the sum.

To evaluate the sum $18.4+3.2$, write the numbers vertically with aligned decimal and add them as shown below:

$\begin{array}{l}\underset{¯}{\begin{array}{l}18.4\\ +3.2\end{array}}\\ 21.6\end{array}$

Therefore, the sum is 21.6.