Respuesta :

Answer:

14

Step-by-step explanation:

-21+-13+20=14

This is true because when subtracting negatives by negatives you pretty much add them and then when you add a positive to a negative you are technically removing the negative by the amount you are adding.

In short its kind of like using inverse operation in a way.

Hope this helps and have a nice day

Also may I please have a brainliest!!!