CCLS - Math: 6.NS.5

The Number System
Apply And Extend Previous Understandings Of Numbers To The System Of Rational Numbers.
State Standard:
Understand that positive and negative numbers are used together to describe quantities having opposite directions or values (e.g., temperature above/below zero, elevation above/below sea level, credits/debits, positive/negative electric charge); use positive and negative numbers to represent quantities in real-world contexts, explaining the meaning of 0 in each situation.