Evaluate the following arithmetic expressions:
`45+22-:2-7xx8`

Answer

To evaluate the arithmetic expression `45 + 22 ÷ 2 - 7 × 8`, we will follow the order of operations, often remembered by the acronym PEMDAS (Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction (from left to right)).

### Step-by-Step Solution:

1. **Identify the Expression**:
We start with the expression:
\[ 45 + 22 ÷ 2 - 7 × 8 \]

2. **Perform Division**:
According to the order of operations, we first perform the division:
\[ 22 ÷ 2 = 11 \]
Now, substitute this back into the expression:
\[ 45 + 11 - 7 × 8 \]

3. **Perform Multiplication**:
Next, we perform the multiplication:
\[ 7 × 8 = 56 \]
Substitute this back into the expression:
\[ 45 + 11 - 56 \]

4. **Perform Addition**:
Now, we perform the addition:
\[ 45 + 11 = 56 \]
Substitute this back into the expression:
\[ 56 - 56 \]

5. **Perform Subtraction**:
Finally, we perform the subtraction:
\[ 56 - 56 = 0 \]

### Final Answer:
The value of the expression `45 + 22 ÷ 2 - 7 × 8` is:
\[ \boxed{0} \]