- Define and explain Place Value in your own words
- Use key terms such as Prime number accurately
- Apply what you have learned to new examples and questions
- Avoid the common mistakes learners make with this topic
Arithmetic is the grammar of mathematics — the agreed rules for reading and writing numbers so every calculation means the same to everyone.
This lesson focuses on Place Value: read, write and compare large numbers using place value.
Read, write and compare large numbers using place value.
Key ideas
Place value
Each digit's value depends on its position: in 5,042 the 5 is worth five thousand and the 4 is worth forty. Zeros hold the other digits in place.
Equivalent forms
1/2 = 0.5 = 50% — fractions, decimals and percentages are three ways of writing the same amount. Choosing the handiest form makes each calculation easier.
Key term — Prime number: A whole number greater than 1 with exactly two factors: 1 and itself, such as 7 or 13.
Write 3/8 as a decimal.
0.375 — 3 ÷ 8 = 0.375.
Answer: 0.375 — 3 ÷ 8 = 0.375.
- Reading 3.45 as bigger than 3.5 Compare the tenths first: 3.5 is 3.50, which beats 3.45.
- Dropping a decimal place 10% of 40 is 4, not 40 — divide by 10 to find ten per cent.
Practice
7.85 — the third digit, 6, rounds the 4 up to 5.
14 — 3 × 4 = 12, then 2 + 12 = 14.
20 — 80 ÷ 4 = 20.
2 — −4 + 9 = 5, then 5 − 3 = 2.
Quick check
Which of these best defines "Prime number"?
List the factors of 24.
- Place Value: read, write and compare large numbers using place value.
- Place value: Each digit's value depends on its position: in 5,042 the 5 is worth five thousand and the 4 is worth forty.
- Factor: A number that divides another exactly, with no remainder.
- Watch out for: reading 3.45 as bigger than 3.5