Significant figures are the digits in a number that contribute to the accuracy of the number. The first significant figure is the first non-zero digit.

To change a number into another number that is approximately the same value but is easier to work with. E.g. round 561 to the nearest 10 is 560.

Rounding integers to significant figures

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

In the number 50 872, the 8 is the {{ }} significant figure.

Select all the numbers which have 7 as the third significant figure.

Select all the numbers which have zeros that are not needed to preserve the place value of other digits.

Match each number to the correct statement.

Round 40 956.644 to 3 significant figures.

Significant figures are the digits in a number that contribute to the {{ }} of the number.

Select all the numbers which have 6 as the first significant figure.

In the number 45 026, in which column is the first significant figure?

Match each number to its value when it is rounded to one significant figure.

What value could the missing digit be in 5$$\square$$ 265 = 50 000 (to 1 s.f.)?

This lesson will soon be taken down.

Rounding integers to significant figures

Lesson outcome