Break up the parentheses. Double negatives result in a positive sign, and positive with a negative sign will result in a negative sign.  

\(\displaystyle (-1)-(-2)-3+(-4) = -1+2-3-4\)

Next, simplify by adding and subtracting each component from left to right.

\(\displaystyle -1+2-3-4= -6\)

Eliminate the double negatives first.  

Double negatives will result in a positive sign.

\(\displaystyle -(-9)-(-9)-6 = +9+9-6\)

Simplify the terms.

\(\displaystyle 9+9-6 = 18-6 = 12\)

\(\displaystyle -4 - (-3) - 6 - (-12) =\)

\(\displaystyle -4 + 3 - 6 + 12 =\)

\(\displaystyle 5\)

Let's work from left to right since it's only subtraction and addition. Since \(\displaystyle 9\) is greater than \(\displaystyle 5\) and it's positive our answer is positive, but we treat this like a subtraction problem because the \(\displaystyle 5\) is negative. \(\displaystyle 9-5=4\).  Now we have \(\displaystyle 4-7\). \(\displaystyle 7\) is greater than \(\displaystyle 4\) and it's negative so our answer is negative and we treat this like a subtraction problem. \(\displaystyle 7-4=3\), but since our answer should be negative our answer is \(\displaystyle -3\). 

Solve by first combining signs and eliminate the parentheses.

A positive multiplied with a negative sign will give a negative sign.

\(\displaystyle -2+(-9)+(2-9) = -2-9+2-9 = -18\)

In order to solve this problem, we need to start at \(\displaystyle -12\) on the number line. 

Next, we have \(\displaystyle +5\) which means we need to move \(\displaystyle 5\) places to the right on the number line. When we have an addition sign  \(\displaystyle (+)\) we move to the right because that is towards the positive side of the number line. When we have a subtraction sign \(\displaystyle (-)\) we move to the left because that is towards the negative side of the number line. 

The orange arrow moved \(\displaystyle 5\) places to the right, and ended at \(\displaystyle -7\); thus,

\(\displaystyle -12+5=-7\)

In order to solve this problem, we need to start at \(\displaystyle -10\) on the number line. 

Next, we have \(\displaystyle +8\) which means we need to move \(\displaystyle 8\) places to the right on the number line. When we have an addition sign  \(\displaystyle (+)\) we move to the right because that is towards the positive side of the number line. When we have a subtraction sign \(\displaystyle (-)\) we move to the left because that is towards the negative side of the number line. 

The orange arrow moved \(\displaystyle 9\) places to the right, and ended at \(\displaystyle -2\); thus,

\(\displaystyle -10+8=-2\)

In order to solve this problem, we need to start at \(\displaystyle -6\) on the number line. 

Next, we have \(\displaystyle +9\) which means we need to move \(\displaystyle 9\) places to the right on the number line. When we have an addition sign  \(\displaystyle (+)\) we move to the right because that is towards the positive side of the number line. When we have a subtraction sign \(\displaystyle (-)\) we move to the left because that is towards the negative side of the number line. 

The orange arrow moved \(\displaystyle 9\) places to the right, and ended at \(\displaystyle 3\); thus,

\(\displaystyle -6+9=3\)

In order to solve this problem, we need to start at \(\displaystyle -8\) on the number line. 

Next, we have \(\displaystyle +16\) which means we need to move \(\displaystyle 16\) places to the right on the number line. When we have an addition sign  \(\displaystyle (+)\) we move to the right because that is towards the positive side of the number line. When we have a subtraction sign \(\displaystyle (-)\) we move to the left because that is towards the negative side of the number line. 

The orange arrow moved \(\displaystyle 16\) places to the right, and ended at \(\displaystyle 8\); thus,

\(\displaystyle -8+16=8\)

In order to solve this problem, we need to start at \(\displaystyle -15\) on the number line. 

Next, we have \(\displaystyle +8\) which means we need to move \(\displaystyle 8\) places to the right on the number line. When we have an addition sign  \(\displaystyle (+)\) we move to the right because that is towards the positive side of the number line. When we have a subtraction sign \(\displaystyle (-)\) we move to the left because that is towards the negative side of the number line. 

The orange arrow moved \(\displaystyle 8\) places to the right, and ended at \(\displaystyle -7\); thus,

\(\displaystyle -15+8=-7\)