Fill in the missing integers in these math problems.

To solve the problem of filling in the missing integers, we need to determine the value that makes each equation true. Let's go through each equation step by step.

Equation 1: \(0 + (-13) = \_\_\_\)

- Adding 0 to any number does not change the number.
- Therefore, \(0 + (-13) = -13\).

Equation 2: \(\_\_\_ + 21 = 7\)

- Let the missing integer be \(x\). The equation becomes \(x + 21 = 7\).
- To solve for \(x\), subtract 21 from both sides:
\[
x = 7 - 21 = -14
\]

Equation 3: \(-9 + \_\_\_ = -10\)

- Let the missing integer be \(y\). The equation becomes \(-9 + y = -10\).
- To solve for \(y\), add 9 to both sides:
\[
y = -10 + 9 = -1
\]

Equation 4: \(-18 + \_\_\_ = 6\)

- Let the missing integer be \(z\). The equation becomes \(-18 + z = 6\).
- To solve for \(z\), add 18 to both sides:
\[
z = 6 + 18 = 24
\]

Equation 5: \(\_\_\_ + (-5) = -5\)

- Let the missing integer be \(w\). The equation becomes \(w + (-5) = -5\).
- Simplify the equation:
\[
w - 5 = -5
\]
- Add 5 to both sides:
\[
w = -5 + 5 = 0
\]

Equation 6: \(-11 + \_\_\_ = 0\)

- Let the missing integer be \(a\). The equation becomes \(-11 + a = 0\).
- To solve for \(a\), add 11 to both sides:
\[
a = 0 + 11 = 11
\]

Equation 7: \(6 + (-8) = \_\_\_\)

- Perform the addition:
\[
6 + (-8) = 6 - 8 = -2
\]

Equation 8: \(\_\_\_ + (-16) = 19\)

- Let the missing integer be \(b\). The equation becomes \(b + (-16) = 19\).
- Simplify the equation:
\[
b - 16 = 19
\]
- Add 16 to both sides:
\[
b = 19 + 16 = 35
\]

Equation 9: \(100 + (-11) = \_\_\_\)

- Perform the addition:
\[
100 + (-11) = 100 - 11 = 89
\]

Equation 10: \(\_\_\_ + 0 = 12\)

- Let the missing integer be \(c\). The equation becomes \(c + 0 = 12\).
- Adding 0 does not change the number:
\[
c = 12
\]

Equation 11: \(1.2 + 1.3 = \_\_\_\)

- Perform the addition:
\[
1.2 + 1.3 = 2.5
\]

Equation 12: \(\_\_\_ + 20 = 0\)

- Let the missing integer be \(d\). The equation becomes \(d + 20 = 0\).
- To solve for \(d\), subtract 20 from both sides:
\[
d = 0 - 20 = -20
\]

Equation 13: \(14 + \_\_\_ = -16\)

- Let the missing integer be \(e\). The equation becomes \(14 + e = -16\).
- To solve for \(e\), subtract 14 from both sides:
\[
e = -16 - 14 = -30
\]

Final Answer:

\[
\boxed{-13, -14, -1, 24, 0, 11, -2, 35, 89, 12, 2.5, -20, -30}
\]