Year 7 · History · Historical skills
Dating and sequencing the past
Learners use BCE and CE, centuries and millennia, and construct timelines across long time spans.
Awaiting educator review. This material was drafted by our content team with AI assistance and is waiting for review by a qualified educator. Please check it suits your child before using it. Created 10 October 2026.
Learning goals
Learners will
- Use BCE and CE dating conventions correctly.
- Identify the century a year belongs to.
- Calculate time spans between dates in the same era.
Success looks like
- I can explain what BCE and CE mean.
- I can name the century of a given year.
- I can order BCE dates correctly on a timeline.
The big idea
Many societies have their own calendars. Historians around the world commonly use the system of BCE (Before Common Era) and CE (Common Era). These match the older labels BC and AD.
There is no year 0. The year 1 BCE is followed directly by 1 CE.
BCE years count backwards: 500 BCE is earlier than 300 BCE. On a timeline, larger BCE numbers sit further to the left.
A century is 100 years. The 1st century CE is years 1–100, the 2nd century is 101–200, and so on. So the century number is one more than the 'hundreds' digit for most years: 1788 is in the 18th century and 2026 is in the 21st century. BCE centuries work the same way backwards: 450 BCE is in the 5th century BCE.
To find time between two dates in the same era, subtract the smaller number from the larger. For example, from 753 BCE to 509 BCE is 753 − 509 = 244 years.
When one date is BCE and the other is CE, add the two numbers and subtract 1 (because there is no year 0). From 100 BCE to 100 CE is 100 + 100 − 1 = 199 years.
Dates from the deep past are often given as 'years ago' or with c. (circa) because they are estimates. For example, archaeological evidence shows First Nations peoples have lived in Australia for at least 50,000 years, and research at some sites suggests 65,000 years or more.
Worked examples
Ordering BCE dates
Order from earliest to latest: 27 BCE, 753 BCE, 476 CE, 509 BCE.
- BCE dates come before CE dates.
- Among BCE dates, bigger numbers are earlier: 753, then 509, then 27.
- Then 476 CE.
Answer: 753 BCE → 509 BCE → 27 BCE → 476 CE.
Finding the century
Which century is the year 1901 in?
- The 20th century runs from 1901 to 2000.
- 1901 is the first year of that range.
Answer: The 20th century.
Time span across eras
How many years from 31 BCE to 14 CE?
- Add the numbers: 31 + 14 = 45.
- Subtract 1 because there is no year 0: 45 − 1 = 44.
Answer: 44 years.
Practice check
Have a go, then check your answers. Each answer comes with an explanation.
Answer guide for parents
Which date is earliest?
500 BCE — Larger BCE numbers are further in the past.
Which century is 1788 in?
18th century — The 18th century covers 1701–1800.
What does 'c.' before a date mean?
Circa, or approximately — Circa means about or approximately.
Which year comes directly after 1 BCE?
1 CE — There is no year 0; 1 BCE is followed by 1 CE.
A millennium is how many years?
1,000 — A millennium is 1,000 years.
How many years from 753 BCE to 509 BCE?
244 — Both are BCE, so subtract: 753 − 509 = 244.
Which century (number only) is the year 2026 in?
21 — The 21st century runs from 2001 to 2100.
How many years from 1606 CE to 1788 CE?
182 — 1788 − 1606 = 182.
Watch out for
- Learners often think 1700s means the 17th century. The 1700s are the 18th century.
- Many assume there was a year 0. There was not, which matters when calculating across BCE and CE.
- Some think BCE dates count forwards like CE dates, so they order 100 BCE before 500 BCE.
Tips for parents
- Use a long tape measure as a timeline, for example 1 cm = 10 years, to show how vast deep time is.
- Ask quick oral questions such as 'What century was your grandparent born in?'
- When discussing how long First Nations peoples have lived in Australia, explain that figures come from archaeological dating and may be revised as research continues, and that First Nations communities hold their own understandings of their histories.
Go further
- Build a scaled timeline of the last 65,000 years and mark key events from Australia and the ancient world.
- Find out about a calendar used in another culture, such as the Chinese or Islamic calendar.
- Research how radiocarbon dating works and what its limits are.