Worksheet for calculating angles on a straight line, suitable for 5th-grade math practice.

Problem Description:

The task is to calculate the angles on a straight line for each of the given diagrams. The key concept here is that the sum of angles on a straight line is always 180°. Therefore, if one angle is given, the other angle can be calculated as:

\[
\text{Missing angle} = 180^\circ - \text{Given angle}
\]

Solution:

Let's solve each part step by step:

---

#### Diagram 1:
- Given angle: \(40^\circ\)
- Missing angle:
\[
180^\circ - 40^\circ = 140^\circ
\]

#### Diagram 2:
- Given angle: \(70^\circ\)
- Missing angle:
\[
180^\circ - 70^\circ = 110^\circ
\]

#### Diagram 3:
- Given angle: \(130^\circ\)
- Missing angle:
\[
180^\circ - 130^\circ = 50^\circ
\]

#### Diagram 4:
- Given angle: \(25^\circ\)
- Missing angle:
\[
180^\circ - 25^\circ = 155^\circ
\]

#### Diagram 5:
- Given angle: \(145^\circ\)
- Missing angle:
\[
180^\circ - 145^\circ = 35^\circ
\]

#### Diagram 6:
- Given angle: \(124^\circ\)
- Missing angle:
\[
180^\circ - 124^\circ = 56^\circ
\]

#### Diagram 7:
- Given angle: \(61^\circ\)
- Missing angle:
\[
180^\circ - 61^\circ = 119^\circ
\]

#### Diagram 8:
- Given angle: \(69^\circ\)
- Missing angle:
\[
180^\circ - 69^\circ = 111^\circ
\]

---

Final Answers:

\[
\boxed{
\begin{aligned}
1. & \ 140^\circ \\
2. & \ 110^\circ \\
3. & \ 50^\circ \\
4. & \ 155^\circ \\
5. & \ 35^\circ \\
6. & \ 56^\circ \\
7. & \ 119^\circ \\
8. & \ 111^\circ
\end{aligned}
}
\]