What Is a Decimal?
Mathematics · Fractions, Decimals and Percentages · Grades 3–6
Meaning at a glance
A decimal is a number that uses a decimal point to show parts that are smaller than one.
Also searched as: decimals, decimal point, decimal number, decimal numbers, tenths.
Understand it simply
The dot in a decimal is called the decimal point. Digits to its left are whole numbers. Digits to its right are parts of one.
The first place after the point is tenths. So 0.1 means 1 tenth, the same as 1/10, and 0.5 means 5 tenths, the same as 5/10 or 1/2. The second place is hundredths, so 0.25 means 2 tenths and 5 hundredths.
See it work
Cut a bar into 10 equal parts and shade 3 of them. You have shaded 3/10 of the bar. Written as a decimal, that is 0.3.
Avoid this confusion
A longer decimal is not a bigger decimal. 0.5 is bigger than 0.25, even though 25 is bigger than 5. Compare place by place: 0.5 is 5 tenths, and 0.25 is only 2 tenths and a bit.
0.3 and 0.03 are different. The first is 3 tenths. The second is 3 hundredths, which is ten times smaller.
Try it yourself
Work these out first, then check your answers below.
Write 7/10 as a decimal.
Which is bigger, 0.4 or 0.35?
What does the 8 mean in 2.18?
Check your understanding
Show the answer to question 1
Answer: 0.7
Seven tenths is written 0.7.
Show the answer to question 2
Answer: 0.4
0.4 is the same as 0.40, which is 40 hundredths. 0.35 is 35 hundredths.
Show the answer to question 3
Answer: 8 hundredths
The first digit after the point is tenths (1). The second is hundredths (8).
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You now know what decimal means. Keep going with a full lesson, then explore the ideas that connect to it.
Learn
Learn this in a full lesson.
- Decimal place value (Grade 4)
- Writing decimals (Grade 4)
- Understanding tenths (Grade 4)
- Fractions and decimals (Grade 4)
- Decimal place value (Grade 5)
Practise
Practise with Learning Lab questions for the lesson Decimal place value (Grade 4), with an explanation after each answer.
Explore
Ideas that connect to this word.
- Fraction: a decimal is another way to write some fractions.
- Place value: decimals continue the place value pattern to the right of the point.
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Sources and review
This explanation was written from Courseversity lesson content (see the lessons above). An outside reference check is still on the editorial to-do list.
Written by: Courseversity editorial team (AI-assisted draft).
Review status: checked against the sources above. Educator review is pending, so please tell us if anything looks wrong.
Last updated: 27 October 2026.