Answer:
the number is 87
Step-by-step explanation:
the photo contains step by step
Following expressions will have negative product

Following expressions will have positive product

Further explanation:
We will see at each expression one by one
First expression is:

In the given expression one term is positive and one term is negative. The product of negative and positive terms is negative.
Second Expression is:

Both terms are negative and the product of two negative terms is positive.
Third Expression is:

The expression has one positive and one negative term so the product will be negative
Fourth Expression is:

Both terms are positive so the product will also be positive
Keywords: Product, Expressions
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Total sets of 4-digits = 6
Total 4-digit numbers formed by one set of number = 4
So, total numbers that can be formed = 6 × 4 = 24