I.e., (-2)*1=-2 but (-2)*(-1)=2
In: Mathematics
Think about it like walking on the numbers line. A positive number means you go to the right, along the positive x-axis; and a netative number means you go to the left, along the negative direction. When you move -3 spits, you could say that you’re moving 3×(-1) spots. Similarly, movibg 3×(-4) can be seen as 3×(-1)×4. And because multiplication is commutative, it can be seen as (-1)×3×4, or -(3×4), because multiplication is associative. So when you multiply with a negative number, you can see it as turning around, and moving in the direction you’re now facing. This means that something like -3×(-4) can be seen as:
(-1)×3×(-1)×4=
(-1)×(-1)×(3×4)=
-(-(3×4))
By default, you’re looking in the positive direction. Now you need to move a total of 3×4 strps in some direction. Initially, it’s in the positive way (because of PEMDAS: parentheses first). Then you move outward, and get to a minus sign, do you turn around. After that you encounter another minus sign. So you turn around again. And now you’re facing back in the original direction.
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