Answer:
1. -5.7
Step-by-step explanation:
When a negative number and another negative number are being added together (but this differs in multiplication and division though), the answer will always be negative, unless a greater positive (combination or single) number is being added to those, but in this case, it is just two negative numbers. What you can do here is add the absolute values of the negative numbers, which would be 1.8 + 3.9, since absolute values are always positive numbers. Once you add these values, which gives you 5.7, you make the answer negative, because before, you were adding negative numbers, so your answer would be -5.7.
Just so you can make sure your answers are correct for the next ones:
2. -2
3. -4.4
