Rounding
Significant Figures
Decimal Places
Upper & Lower Bounds
Problem-Solving Questions
100

Round 248.67 to the nearest ten.

What is 250?

100

Write 0.00456 to 2 significant figures.

What is 0.0046?

100

Round 23.678 to 1 decimal place.

What is 23.7?

100

The lower bound of 6.5 rounded to 1 decimal place.

What is 6.45?

100

A rectangular garden is measured to be 8.2 m long and 4.6 m wide, both to the nearest 0.1 m.
Work out the maximum possible area of the garden.  

Max length = 8.25, Max width = 4.65
Max area = 8.25 × 4.65 = 38.3625 m²  

200

This is the result of rounding 9.876 to 1 decimal place.

What is 9.9?

200

The number of significant figures in 10200.0

What is 6?

200

This is the result of rounding 5.449 to 2 decimal places.

What is 5.45?

200

The upper bound of 3.76 to 2 decimal places.

What is 3.765?

200

A square tile has a side of 15 cm, measured to the nearest cm.
What is the minimum possible area of the tile?

Min side = 14.5 cm
Min area = 14.5 × 14.5 = 210.25 cm²

300

Round 134.59 to the nearest whole number.

What is 135?

300

Round 3.1459 to 3 significant figures.

What is 3.15?

300

This number rounds to 7.9 when rounded to 1 decimal place. It is greater than 7.85.

What is any number between 7.85 and 7.949...

300

The lower and upper bounds of 40, rounded to the nearest 10.

What are 35 and 44.999...?

300

The length of a plank is measured as 2.5 m, correct to the nearest 0.1 m.
It is used to build 4 shelves of equal length.
What is the maximum possible length of each shelf?

Min length = 2.45 m (less wood available)
2.45 ÷ 4 = 0.6125 m

400

This number, when rounded to the nearest hundred, becomes 700.

What is any number from 650 to 749?

400

This number, when rounded to 1 significant figure, becomes 5000.

What is any number from 4500 to 5499?

400

The smallest number that rounds to 8.3 when rounded to 1 decimal place.

What is 8.25?

400

If a length is measured as 12.0 cm to 1 decimal place, its lower bound is this.What is 11.95 cm?

What is 11.95 cm?

400

A car travels 65 km in 1.2 hours.
Both measurements are rounded to the nearest km and nearest 0.1 hour.
Calculate the minimum possible average speed of the car.

Min speed = Min distance / Max time = 64.5 ÷ 1.25 = 51.6 km/h

500

This is the smallest number that rounds to 850 when rounded to the nearest ten.

What is 845?

500

The largest number that rounds to 6.70 when given to 3 significant figures.

What is 6.704?

500

Round 91.9865 to 3 decimal places.

What is 91.987?

500

A mass is 65 kg rounded to the nearest kg. What are its bounds?

What are 64.5 kg and 65.5 kg?

500

A metal rod is cut into 5 equal pieces.
The rod's length is 100 cm, measured to the nearest cm.
Find the minimum possible length of each piece.

Min length = 99.5 cm → 99.5 ÷ 5 = 19.9 cm

M
e
n
u