Interpret timelines
Theory
A timeline places events in order along a line marked with years. Read the year beside a mark for the event, and subtract two years to find the duration between events.
A timeline shows events in order along a line marked with years.
Events are ordered left to right, earliest first. The year beside a mark tells you when the event happened.
The duration between two events is the later year take away the earlier year.
Bigger gaps on the line mean longer times between events, so the marks are not always evenly spaced.
Every duration is a subtraction of two years.
| From | To | Years |
|---|---|---|
| 1850 | 1875 | \(25\) |
| 1875 | 1925 | \(50\) |
| 1875 | 1975 | \(100\) |
How to read a timeline
- Find a year on the line and read the event beside it.
- Order events by their years — the smallest year is earliest.
- Subtract two years to find the duration between events.
- Check long gaps by counting on in parts across a century.
Find \(1900\) and read its label.
| \(1900\) | \(=\) | Railway |
Take the earlier year from the later.
| \(1925-1875\) | \(=\) | \(50\) |
Subtract, or count on in parts.
| \(1975-1875\) | \(=\) | \(100\) |
The earlier event has the smaller year.
| \(1900<1925\) | Railway |
Common pitfalls
Frequently asked questions
How do I read an event on a timeline?
Find the year on the line and read the label beside it. Events are placed in order, earliest on the left.
How do I find the years between two events?
Subtract the earlier year from the later year. That difference is the duration between them.
Are the marks evenly spaced?
Not always. A wider gap stands for more years, so a long wait between two events shows as a longer distance on the line.
How do I subtract across a century?
Count on in parts. From \(1875\) to \(1900\) is \(25\) years, then \(1900\) to \(1975\) is \(75\), which add to \(100\).
Which event happened first?
The one with the smallest year. On the timeline it is the mark furthest to the left.