Skill: Evaluate expressions with addition and subtraction

A numerical expression is a short way to show calculations. To evaluate an expression:

1. Complete any calculation inside parentheses first.
2. Then add or subtract from left to right.
3. Use place value to line up ones, tens, and hundreds.
4. Do not switch the order of numbers in a subtraction.

Example:

$$700-(238+142)+95$$

Step 1: Evaluate the parentheses.

Add $238$ and $142$:

$$\begin{array}{r} 238\\ + 142\\ \hline 380 \end{array}$$

Now the expression is:

$$700-380+95$$

Step 2: Subtract from left to right.

$$700-380=320$$

Now the expression is:

$$320+95$$

Step 3: Add.

$$320+95=415$$

Therefore,

$$700-(238+142)+95=\boxed{415}$$

Remember: the parentheses tell you to add $238$ and $142$ first. Also, subtraction cannot be rearranged. For example, $700-380$ is not the same as $380-700$.