Answer:
you should multiply 4 by -5, 5 times, so 4 times -5 = -20 then multiply by -5 = 100 then multiply y -5 = -500 then multiply by -5 = 2,500 then multiply by -5 equals = -12,500
or just 4 times -5 = -20 because I don't know how they teach you.
So if you will expand it it will be eaither-12,500 or -20, it's how they teach you.