Explanation:
The mathematical sign for the operation is subtraction.
To Solve This You Will Need To;
1] The sign of the product of -35 and -625 is;
It's going to be;
-35--625
The negative sign will turn into addition sign before you can operate it. So it's going to be;
-35+625=590(positive)
It's just like subtracting 35 from 625.
2] The sign of the product of 263 and 0 is;
263-0
With this no quantity is going to be subtracted so the 263 will remain the same.
So 263-0=263(positive)
3] The sign of the product of -21 and 451 is;
-21-451
With this you won't subtract but rather you'll add and when you add the answer is going to be -472
-472(negative)
4] The sign of the product of -350 and 89 is;
-350-89
With this you will add it but you won't subtract the negatives so it's going to be;
-350-89=-439(negative)
Hope I am Correct I didn't really understand your question well. But Good Luck:)