When using negatives for problems such as these, remember three things!
1.) Two "-" signs that are sitting next to each other will always change into a "+" sign.
For example, 4 - (-5) = ? The two "-" signs in between the 4 and 5 become a positive number. It ALWAYS does!
2.) The bigger the number with the negative sign, then the answer will become negative in the end.
For example, 7 - 10 = ? (OR -10 + 7 = ?) The biggest number with the negative sign is "10". Therefore the answer will become negative. When you place -10 on a number line (Number Line is from -10 to 0), add 7 to that -10. This means move 7 spaces to the right since it's a positive 7.
-10, -9, -8, -7, -6, -5, -4, -3....You moved 7 spaces to the right. Now you see your answer is negative 3.
3.) If both numbers are negative and you're <u>adding them</u>, your answer will ALWAYS be negative.
For example, -6 + -7 = ? (This is the same as -6 - 7) Look at these expressions as if you're adding them. 6 + 7 = 13. Now just add the negative sign. -6 - 7 = -13. That would be the answer.
Hope this helps!
Let me know if you need help solving the other problems. I'll gladly explain.