Recall the following properties of multiplication of signed numbers:
(positive)(positive) = positive
(positive)(negative) = negative
(negative)(negative) = positive
When more than two numbers are being multiplied, just count the number of minus signs: any even number of minus signs collapses to a plus sign; any odd number of minus signs collapses to a minus sign.
Examples
The product
$\,(+)(-)(-)(+)(-)\,$ is negative $\,(-)\,.$
In this example, there are $\,3\,$ minus signs;
$\,3\,$ is an odd number.
The product
$\,(-)(-)(+)(-)(-)\,$ is positive $\,(+)\,.$
In this example, there are $\,4\,$ minus signs;
$\,4\,$ is an even number.
Practice
Input your answer as: $\quad+\quad$ or $\quad-$