Starter quiz
- A degree of ______ shows how precise a number or measurement is. Examples are: to the nearest cm, to the nearest 10, to 1 s.f. and 2 d.p.
- 'accuracy' ✓
- Round 15.076 to two decimal places.
- '15.08' ✓
- Round 0.0504 to one decimal place.
- '0.1' ✓
- Round 20.961 to 1 decimal place.
- '21.0' ✓
Calculate the cost of carpeting this area.- '£76.73' ✓
- 3 friends go out for lunch and spend £31. They pay the same amount each. What is the smallest amount they each pay to cover the cost of the bill?
- '£10.34' ✓
Exit quiz
- The first significant figure is the first non-______ digit in a number.
- 'zero' ✓
- Select all the numbers which have 4 as the first significant figure.
- 4698 ✓
- 54 875
- 403 146 ✓
- 644 145
- 4 002 231 ✓
-
- In the number 654 023, in which column is the first significant figure?
- tens
- hundreds
- thousands
- ten thousands
- hundred thousands ✓
-
- Match each number to its value when it is rounded to one significant figure.
- 4 564 231⇔five million ✓
- 52.96⇔fifty ✓
- 48 264⇔fifty thousand ✓
- 5365.12⇔five thousand ✓
- 496 568⇔five hundred thousand ✓
- Round 654 023 to one significant figure.
- '700 000' ✓
- What value could the missing digit be in 3□89 = 4000 (to 1 s.f.)?
- 3
- 4
- 5 ✓
- 6 ✓
- 7 ✓
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Worksheet
Presentation
Video
Lesson Details
Key learning points
- It is possible to use rounding and place value to know the size of a number without knowing the actual number.
- The first non-zero digit of a number is the first significant figure.
- You can identify the place value of the first significant figure.
- A number can be located on a number line and numbers to 1 significant figure either side of it represented.
- Any integer can be rounded to one significant figure and a number line can help with this.
Common misconception
Assuming all zero digits are not significant.
Within the lesson there are many examples where some zeros are significant. Relate significance back to the communication of accuracy and that some digits are significant as they preserve the place value of other digits.
Keywords
Significant figure - 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.
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