Both denominators are 4, so we can add the numerators to place over the common denominator. The numerators are -3 and -3, which add to -6. One way to think of negative numbers is to think of IOUs, which are a way of expressing debt in money. For instance, if you go into a store and buy a $10 item, but only have $3 in your pocket, then you would have to owe the owner $7. This can be represented with -7. If you repeat the process, then you'd have 7+7 = 14 in IOUs total. This would be represented with -14
In short, adding negative numbers is really the same as adding positives, but the final result is negative
So that's why -3+-3 turns into -6. We add the two threes like normal but then make the final result negative. All throughout this process, the denominator stays at 4.
So we end up with -6 over 4 which reduces to -3 over 2. How is this reduction happening? We are simply dividing each piece by the greatest common factor 2.
-6 divided by 2 = -3
4 divided by 2 = 2
