Find the number of even positive numbers which have four digits.

Explanation

To find the number of even positive four-digit numbers, we can break down the problem into manageable steps.

### Step-by-Step Solution:

1. **Understanding the structure of a four-digit number**:
A four-digit number can be represented as \(abcd\), where \(a\), \(b\), \(c\), and \(d\) are the digits. The first digit \(a\) cannot be 0 (as it would then be a three-digit number).

2. **Identifying the last digit (d)**:
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