Answer:
Let us say you must pay someone ten dollars a month. This is the same as being paid negative ten dollars a month. Ten months ago (in negative ten months) you were 100 dollars richer *. (-10)x(-10)=100
Considering only this schedule of payments.
Multiplying by a positive represents adding the same number to zero over and over again. Multiplying by a negative represents subtracting the same number from zero over and over again.
Multiplying a negative by a negative represents subtracting the same negative number from zero over and over again.
You are a struggling college student your Mother takes it on herself to take away your monthly internet bill for 12 months. Your internet bill is $60 a month. Because a bill is something you pay, not something you earn, we will call your bill (-$60). Your Mother is repeatedly taking something away from you for 12 months, we will call that multiplying by -12.
(-12) (-$60) = +$720.
You have an extra $720 to spend because your Mother has taken away something from you