Rounding Significant Figures

Welcome to the Math Salamanders Rounding Significant Figures collection.

Here you will find a selection of free printable rounding Worksheets, which will help your child learn to round numbers to either 1, 2 or 3 significant figures.

Rounding Significant Figures

What does 'Rounding to Significant Figures' mean?

Rounding to ... significant figures means that you are only interested in the first ... digits that make up a number.

You might need to round a number to the nearest 10, 100, 1000, etc., or you might need to round it to 1, 2 or even 3 decimal places.

How many significant figures do I need to round to?

Often when you are dealing with numbers in the real world, you do not need to know the exact answer but simply an approximation.

Rounding to 1 significant figure will give you a rough approximation of what the answer is.

Rounding to 2 significant figures will give you a reasonable approximation of your answer and it is usually enough for most quantities where you do not have to be exact.

Rounding to 3 significant figures will give you a very close approximation of your answer and it is usually the most precise that you will need to be for everyday working out.

How is it different from Rounding to decimal places?

Rounding to significant figures is different from rounding to decimal places.

The first significant figure is the first non-zero digit a number has.

The second significant figure is the digit after the 1st significant figure.

The third significant figure is the digit after the 2nd significant figure, and so on.

See below for help to round a number to a set number of significant figures.

Rounding numbers to 1 significant figure (1SF)

When you are rounding a number to 1 significant figures, you are trying to reduce the number to a single digit and zeros (and possibly a decimal point) to indicate its place value.

How to round a number to 1 significant figure

Look at the 2nd significant digit that the number has.

In a decimal, the first significant digit is the first non-zero digit. The 2nd significant digit is the digit after the first.

  • if it is less than 5 then round the number down by removing the rest of the number after the 1st significant digit and filling in with zeros;
  • if it is 5 or more then round the number up by adding one on to the 1st digit and removing the rest of the number and filling in with zeros.

Examples

  • 8726 rounds up to 9000, because the 2nd significant digit is a 7.
  • 73.283 rounds down to 70 because the 2nd significant digit is a 3.
  • 152 rounds up to 200 because the 2nd significant digit is a 5.
  • 0.003826 rounds up to 0.004 because the 2nd significant digit is an 8.
  • 0.60828 rounds down to 0.6 because the 2nd significant digit is a 0.

Rounding numbers to 2 significant figures (2sf)

When you are rounding a number to 2 significant figures, you are trying to reduce the number to a two digits and zeros (and possibly a decimal point) to indicate its place value.

How to round a number to 2 significant figures

Look at the 3rd significant digit that the number has.

This is the digit which is two digits after the most significant digit.

  • if it is less than 5 then round the number down by removing the rest of the number after the 2nd significant digit and filling in with zeros;
  • if it is 5 or more then round the number up by adding one on to the 2nd significant digit and removing the rest of the number and filling in with zeros.

Examples

  • 5271 rounds up to 5300, because the 3rd significant digit is a 7.
  • 73.483 rounds down to 73 because the 3rd significant digit is a 4.
  • 175 rounds up to 180 because the 3rd significant digit is a 5.
  • 0.003826 rounds down to 0.0038 because the 3rd significant digit is a 2.
  • 0.60828 rounds up to 0.61 because the 3rd significant digit is an 8.

Rounding to 3 significant figures (3sf)

When you are rounding a number to 3 significant figures, you are trying to reduce the number to a 3 digits and zeros (and possibly a decimal point) to indicate its place value.

How to round a number to 3 significant figures

Look at the 4th significant digit that the number has.

  • if it is less than 5 then round the number down by removing the rest of the number after the 3rd significant digit and filling in with zeros;
  • if it is 5 or more then round the number up by adding one on to the 3rd significant digit and removing the rest of the number and filling in with zeros.

Examples

  • 5261 rounds down to 5260, because the 4th significant digit is a 1.
  • 73.285 rounds up to 73.3 because the 4th significant digit is an 8.
  • 1805 rounds up to 1810 because the 4th significant digit is a 5.
  • 0.003826 rounds up to 0.00383 because the 4th significant digit is a 6.
  • 0.07284 rounds down to 0.0728 because the 4th significant digit is a 4.

Rounding Significant Figures Worksheets

Here you will find a range of free printable rounding worksheets to help your child learn to round numbers to either 1,2 or 3 significant figures.

These sheets are carefully graded so that the easier sheets come first and give extra support.

Each sheet comes with a separate printable answer sheet.

Using these sheets will help your child to:

  • round numbers to the nearest 1,2 or 3 significant figures.

All the free Rounding Worksheets in this section support the Elementary Math Benchmarks.

Rounding Significant Figures Worksheets to 1sf

Rounding Significant Figures Worksheets to 2sf

Rounding Significant Figures Worksheets to 1sf & 2sf

Rounding Significant Figures Worksheets to 1sf & 2sf & 3sf

Looking for something easier?

The rounding numbers worksheets in this section involve rounding numbers to the nearest 10.

They are at a more basic level than those on this page.

More Recommended Math Worksheets

Take a look at some more of our worksheets similar to these.

Online Rounding Practice Zone

In our Rounding Practice zone, you can practice rounding a range of numbers. You can round numbers to the nearest 10, 100 or even 1000. Want to round numbers to the nearest decimal place, you can do that too!

Select the numbers you want to practice with, and print out your results when you have finished.

You can also use the practice zone for benchmarking your performance, or using it with a group of children to gauge progress.

Rounding Challenges to the nearest 10, 100 or 1000

Here is our rounding challenges collection which will give your child an opportunity to apply their rounding learning.

The challenges can be tackled individually or with a partner.

Each challenge involves using rounding knowledge and properties of numbers to work out the correct answer.

Using these sheets will help your child to:

  • apply their knowledge of rounding to the nearest 10, 100 or 1000;
  • develop their problem solving skills;
  • develop their understanding about place value and properties of numbers.

All the rounding challenges support elementary math benchmarks.

Rounding Decimals Challenges

On this webpage, you will find a larger selection of our rounding decimals challenges.

The challenges involve rounding numbers to the nearest 1, 0.1 or 0.01.

Each challenge involves using rounding knowledge and properties of numbers to work out the correct answer.

Using these sheets will help your child to:

  • apply their knowledge of rounding to the nearest one, tenth or hundredth;
  • develop their problem solving skills;
  • develop their understanding about decimal place value and properties of numbers.

All the rounding challenges support elementary math benchmarks.

4th Grade Place Value Worksheets

Here you will find a range of Free Printable 4th Grade Decimal Place Value Worksheets.

The following worksheets involve using and understanding decimal notation - tenths and hundredths.

Using these sheets will help your child to:

  • Understand decimals;
  • Use place value notation with tenths and hundredths;
  • Know how to read and write numbers to 10 million;
  • Understand place value to 10 million.

All the Free 4th Grade Math Worksheets in this section are informed by the Elementary Math Benchmarks for 4th Grade.

 

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How to Print or Save these sheets

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Need help with printing or saving?
Follow these 3 easy steps to get your worksheets printed out perfectly!

 

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