Rounding

By rounding each number to 1 significant figure, estimate the value of

You must show your working.

Is your answer to part (a) an overestimate or an underestimate? Tick one box.

Give a reason for your answer.

The length of a fence panel is 160 cm to the nearest 10 cm

Complete the error interval.

A different fence panel measures 2 metres to the nearest 10 cm Kim says that the total length of three of these fence panels must be less than 6.2 m

Show that Kim is correct.

The length of a fence panel is 160 cm to the nearest 10 cm

Complete the error interval.

A different fence panel measures 2 metres to the nearest 10 cm Kim says that the total length of three of these fence panels must be less than 6.2 m

Show that Kim is correct.

When w is truncated the answer is 8 Sacha writes the error interval due to truncation as 7.5 w 8.5

Give a reason why Sacha is wrong and state the correct error interval f or w.

Give your answer to 2 decimal places.

The length of a wall is 9 metres to the nearest metre. Complete the error interval for the length of the wall.

Here is a list of four numbers.

6.92 7.27 7.18 7.14

Use one number from the list to complete each statement.

Here is a list of six numbers.

– 10 – 5 – 2 4 6 10

Use two numbers from the list to complete each statement.

Connor is estimating the answer to 385 + 1479

He rounds each number to the nearest 10

Work out his estimate.

Connor says, “My estimate will be more than the exact answer.”

How does he know this without working out the exact answer ?

Here is a cuboid.

Work out the volume of the cuboid. Give your answer to 1 decimal place.

The length of a line is 8 cm to the nearest centimetre.

Complete the error interval.

The length of a line is 8 cm to the nearest centimetre.

Complete the error interval.

Millie is estimating the value of

She rounds each decimal number to 1 significant figure.

Work out Millie’s estimate. You must show your working.

Millie says, “My estimate must be more than the exact value.” Without working out the exact value, give a reason how she can know this.

Millie is estimating the value of

She rounds each decimal number to 1 significant figure.

Work out Millie’s estimate. You must show your working.

Millie says, “My estimate must be more than the exact value.” Without working out the exact value, give a reason how she can know this.

This scale drawing of a bus has length 8 cm

The actual length of the bus is 3.8 times the actual length of a car. Work out the actual length of the car. Give your answer in metres, to the nearest centimetre.

Part of a running track is the arc of a semicircle joined to a straight line. The semicircle has diameter 45 metres. The straight line has length 75 metres.

Abby runs once along this part of the track in 18 seconds. Work out her average speed. Give your answer to 2 significant figures.

Round 2.84 to 1 decimal place.

The mass of a baby is 3.6 kilograms to 1 decimal place. What is the error interval for the mass in kilograms? Tick one box.

The mass of a baby is 3.6 kilograms to 1 decimal place. What is the error interval for the mass in kilograms? Tick one box.

What is 6.2819 to 2 decimal places? Circle your answer.

6.2 6.28 6.29 6.3

Give your answer to 2 decimal places.

When rounded to 3 significant figures, x = 6.37 Circle the correct error interval.

Give your answer as a decimal. Write down your full calculator display.

Is your answer to part (a) sensible? Check by rounding each of 9.75, 1.875 and 6.4 to the nearest whole number. You must show your working.

Tick a box.

The height of a tree is 12 metres, correct to the nearest metre. Circle the error interval.

The length of a table is 110 cm to the nearest cm Complete the error interval.

The length of a table is 110 cm to the nearest cm Complete the error interval.

By rounding each number to the nearest 10,

You must show your working.

Write down your full calculator display.

Give your answer to part (a) to 1 decimal place.