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      Rounding integers to significant figures

      Lesson details

      Learning outcome

      I can round integers to a required number of significant figures.

      Key learning points

      1. The first non-zero digit of a number is the first significant figure.
      2. Once the first significant figure is identified you can find any significant figure.
      3. It is important to know when zeros are and are not significant when rounding integers.
      4. Integers can be rounded to any number of significant figures.

      Keywords

      • Significant figures - 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.

      • Round - 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.

      Common misconception

      Assuming all zero digits are not significant.

      Designing questions that contain zero digits in a variety of positions.

      Teacher tip

      Using the same cross-number grid or a simplified version, challenge pupils to come up with their own questions and answers. Ensuring that all numbers fit and coming up with appropriate questions with the correct number of significant figures will ensure a deep understanding of significant figures.

      Licence

      This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0
      except where otherwise stated. See Oak's terms & conditions
      (Collection 2).

      Lesson video

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      Prior knowledge starter quiz

      6 Questions

      Q1.
      Significant figures are the digits in a number that contribute to the of the number.

      Correct Answer: accuracy

      Q2.
      Select all the numbers which have 6 as the first significant figure.

      46
      Correct answer: 68
      Correct answer: 606
      46 266
      Correct answer: 600 606

      Q3.
      In the number 45 026, in which column is the first significant figure?

      tens
      hundreds
      thousands
      Correct answer: ten thousands
      hundred thousands

      Q4.
      Match each number to its value when it is rounded to one significant figure.

      Correct Answer:356 268,four hundred thousand

      four hundred thousand

      Correct Answer:42.689,forty

      forty

      Correct Answer:449.09,four hundred

      four hundred

      Correct Answer:3 591 054,four million

      four million

      Correct Answer:3560,four thousand

      four thousand

      Q5.
      Round 85 026 to one significant figure.

      Correct Answer: 90 000

      Q6.
      What value could the missing digit be in 5$$\square$$ 265 = 50 000 (to 1 s.f.)?

      7
      6
      5
      Correct answer: 4
      Correct answer: 3

      6 Questions

      Q1.
      In the number 50 872, the 8 is the significant figure.

      Correct Answer: third, 3rd

      Q2.
      Select all the numbers which have 7 as the third significant figure.

      Correct answer: 507
      Correct answer: 827.04
      12 076.59
      Correct answer: 507 365
      8 005 729

      Q3.
      Select all the numbers which have zeros that are not needed to preserve the place value of other digits.

      60.006
      6006.06
      Correct answer: 60 660.0600
      66 000
      Correct answer: 606 606.66000

      Q4.
      Match each number to the correct statement.

      Correct Answer:5094,4 is the fourth significant figure

      4 is the fourth significant figure

      Correct Answer:50 904 ,4 is the fifth significant figure

      4 is the fifth significant figure

      Correct Answer:509 004,4 is the sixth significant figure

      4 is the sixth significant figure

      Correct Answer:954 000,4 is the third significant figure

      4 is the third significant figure

      Correct Answer:4 050 090 ,4 is the first significant figure

      4 is the first significant figure

      Q5.
      Round 50 904 to 2 significant figures.

      Correct Answer: 51 000

      Q6.
      Round 40 956.644 to 3 significant figures.

      Correct Answer: 41 000

      To help you plan your 8 maths lesson on: Rounding integers to significant figures, download all teaching resources for free and adapt to suit your pupils' needs...