A timeline shows events in order, from earlier on the left to later on the right. Like any scale, only some years are labelled. Work out what each small mark is worth from the labels: 10 years split into 5 spaces is 2 years a mark. To find how long between two events, count on from the earlier year to the later one. To place an event that happened some years later, start at the first event and move right.
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Move the hands
3:00
The short hand moves between hour numbers as the minutes pass. One full turn of the long hand is sixty minutes.
Words to know
- timeline
- a line that shows when events happened, in order
- interval
- the time between two marks or two events
- decade
- a period of 10 years
Worked examples
The school opened in 1935 and the pool was built in 1970. How many years later was the pool built?
- 1.Count on from 1935 to 1940: 5 years. Then 1940 to 1970: 30 years.
- 2.5 + 30 = 35.
= 35
Marks every 2 years. A dot is 3 marks after 1940. What year is it?
- 1.Each mark is 2 years: 3 × 2 = 6.
- 2.1940 + 6 = 1946.
= 1946
The school opened in 1936. The pool was built 12 years later. Letters mark 1948, 1960, 1924 and 1932. Which year shows the pool?
- 1.Later means to the right: 1936 + 12.
- 2.1936 + 12 = 1948.
= 1948
For parents
Method: Find the value of one mark, then count on
What to say: What is one mark worth on this timeline? Which way is later?
Common mistakes:
- Counts both the starting year and the end year, so a gap comes out one year too long.
- Treats each small mark on the timeline as 1 year, whatever the marks are worth.
- Subtracts the years column by column, always taking the smaller digit from the larger one.
- Counts the labelled mark as the first step, so reads one mark too late.
- Reads the labelled year just before the dot and ignores the extra marks.
- Counts backwards in time for 'later' (or forwards for 'earlier').
- Counts the years from the start of the timeline instead of from the event.