Key learning points

1. It is possible to use rounding and place value to know the size of a number without knowing the actual number.
2. The first non-zero digit of a number is the first significant figure.
3. You can identify the place value of the first significant figure.
4. A number can be located on a number line and numbers to 1 significant figure either side of it represented.
5. Any integer can be rounded to one significant figure and a number line can help with this.

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.

Common misconception