Final answer:
The temperature at 6 am is -5°C, found by subtracting 8°C (the decrease) from 3°C (the starting temperature).
Step-by-step explanation:
The situation you're describing involves the simple concept of subtraction in mathematics. If the temperature is 3°C at midnight and falls by 8°C by 6am, we will subtract 8°C from 3°C to find the new temperature at 6am. So, we have: 3°C - 8°C = -5°C. Hence, the temperature at 6 am is -5°C.
Learn more about Subtraction