Truncation is the simplifying a number by 'cutting off' one or more of the digits and replacing them with zeros if necessary to preserve place value.

A degree of accuracy shows how precise a number or measurement is.

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Maths

In this unit, pupils have learnt how to round to a given number of decimal places or significant figures and explored the effect of using rounded numbers for calculations. In the future unit, pupils will investigate the bounds and perform calculations to determine a best/worst case scenario.

The prior unit on place value allowed pupils to develop the skills needed to estimate and round values. By understanding the value of each digit, pupils can determine what other values are close to the original value. This unit continues the exploration of the infinite nature of sets of numbers.

Estimation and rounding

__________ is the simplifying a number by 'cutting off' one or more of the digits and replacing them with zeros if necessary to preserve place value.

Match each number with its truncated value to 1 significant figure.

Truncate 49.999999 to 3 significant figures. Select the correct response.

Jacob thinks of a number. Truncated to 1 s.f. Jun's number is 100. Jun's number is a multiple of 8 and it is 105 when rounded to the nearest 5.

A length of wood 37 m needs to be cut into 5 equal strips.

A meal is £37 and you share it between 5 people and want to give a tip

You have £37 and want to buy as many £5 puzzle cubes as possible. 

Match the appropriate treatment of the answer (exact, rounded to truncated) to each context.

In computer science, ‘INT’ or ‘int’ is used to truncate a number so to only give the integers. For example, INT(56/10) has an output of 5. Match each computer instruction to its output.

__________ shows how precise a number or measurement is.

A square plot of grass has a length of 2.89 m to 2 decimal places. Select the correct estimate for the area of the square grass plot.

Which of the following are correct, quick estimate calculations for $${4.56\times8.95} \over {0.498}$$?

Match each calculation to its correct approximate answer. 

This lesson will soon be taken down.

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Lesson outcome