The temperature today is 7 degrees celsius. Yesterday it was 13 degrees celsius cooler. What was the temperature yesterday?

The yesterday's temperature is 6°C below the zero degree Celsius or (-6) degree Celsius.

Step-by-step explanation:

The temperature today is 7 degrees Celsius. Yesterday was 13 degrees Celsius cooler. That the temperature is colder means that the temperature was lower than today's temperature. This means that to obtain the temperature on the previous day, 13°C must be subtracted from today's temperature.

yesterday's temperature=today's temperature-13°C

It is now possible to replace today's temperature with 7 ° C

yesterday's temperature=7°C-13°C

Remember that to subtract two integers of a different sign (one positive and the other negative), as in this case, you must subtract their absolute values (that is, subtract 13-7 = 6), and the answer will have the same sign as the number with the highest absolute value (absolute value or module of any real number is the same number but with a positive sign). As in absolute value 13 is greater than 7, the answer to the subtraction will be negative

yesterday's temperature=7°C-13°C

So, finally, the yesterday's temperature is 6°C below the zero degree Celsius or (-6) degree Celsius.

The temperature yesterday was - 6 because 7-13 is - 6.