Find the sum of the products of the ten numbers `+-1,+-2,+-3,+-4,a n d+-5` taking two at a time.

Explanation

To find the sum of the products of the ten numbers \( \pm 1, \pm 2, \pm 3, \pm 4, \pm 5 \) taken two at a time, we can follow these steps:

### Step 1: Identify the Numbers
The numbers we are considering are:
\[ 1, -1, 2, -2, 3, -3, 4, -4, 5, -5 \]

### Step 2: Calculate the Products of Pairs
We need to calculate the sum of the products of these numbers taken two at a time. The pairs can be formed as follows:
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