Significant figures

Significant figures

Significant figures are the digits in an answer that are considered relevant in the accuracy of the answer.

How to round

• Significant figures are

  counted from left to right starting at the first non-zero digit.

   

• When using scientific

  notation, only the first significant figure sits to the left of the

  decimal point.

   

• Calculators can be

  used to work with scientific notation.

Example 1

Round 8 638 902  to 3 significant figures.

Round 8 638 902  to 3 significant figures.

• First three significant figures starting from left are 8, 6 and 3

• Fourth digit is 5 or more - Round up

• so it is 8 640 000

Multiple Choice

Round 57263 to 3 significant figures.

• 57263

• 57270

• 57300

• 57260

Example 2

Round 400 023  to 3 significant figures

Round 400 023  to 3 significant figures.

• First three significant figures starting from left are 4, 0 and 0

• Fourth digit is less than 5 - NO round up

• so it is 400 000

Multiple Choice

Round 38041 to 3 significant figures.

• 38000

• 38040

• 38100

• 38041

Example 3

Round 0.0056 189  upto 3 significant figures

Round 0.0056189  to 3 significant figures.

• First three significant figures starting from left are 5, 6 and 1

• Fourth digit is 5 or more - round up the third significant figure

• so it is 0.00562

• Do not replace digits 8 and 9 with 0's as it will have 5 significant figures then.

Multiple Choice

Round 0.0019482 upto 3 significant figures

• 0.0019482

• 0.00195

• 0.0019400

• 0.0019500

State the number of significant figures

• 38041

• 0.00521

• 451000

• 256010

The number of significant figures in

• 38041 are 5

• 0.00521 are 3

• 451000 are 3, 4, 5 or 6

• 256010 are 5 or 6.

Multiple Choice

State the number of significant figures in 242300

• 4

• 5

• 6

• all 4, 5 or 6

• none

Multiple Choice

State the number of significant figures in 0.006859

• 7

• 6

• 5

• 4

Multiple Choice

State the number of significant figures in 0.172046

• 3

• 4

• 5

• 6