Decimal place value and rounding

Place value in decimals (tenths, hundredths, thousandths), comparing decimals, and rounding to a given number of decimal places.

Decimal place value

After the decimal point the places are tenths, hundredths, thousandths, and so on. In $3.172$, the $1$ is worth $\tfrac{1}{10}$, the $7$ is worth $\tfrac{7}{100}$ and the $2$ is worth $\tfrac{2}{1000}$.

Rounding decimals

Example 1●

Round $4.2685$ to (a) 1 decimal place and (b) 2 decimal places.

(a) $4.3$

Next digit is 6.

(b) $4.27$

Next digit is 8, so 6 becomes 7.

Example 2●●

Round $12.996$ to 2 decimal places.

The next digit is $6$, so round the $9$ up. That carries: $12.99 \to 13.00$.

Answer: $13.00$ (keep both zeros to show 2 decimal places).

Flashcards

Value of 4 in 0.042

4 hundredths, $\tfrac{4}{100}$

Which is bigger, 0.6 or 0.58?

$0.6$ (it is $0.60$)

$7.349$ to 1 d.p.

$7.3$

Practice

Round $4.2685$ to 1 decimal place.
Round $4.2685$ to 2 decimal places.
Round $12.996$ to 2 decimal places.
Which is largest?
What is the value of the $3$ in $5.731$?
Round $7.349$ to 1 decimal place.
Round $0.06666$ to 3 decimal places.
Round $8.5$ to the nearest whole number.