Significant Figures

Significant Figures

Significant Figures

• Every digit of a number used to express it to the required degree of accuracy, starting from the first nonzero digit.

• There are 5 rules to determine how many "sig figs" a number has...​

Rule #1

ALL non-zero digits DO count!

​498

​

​

​3 sig figs!

​2 sig figs!

​1 sig fig!

​79

​2

Rule #2

Zeros to the right of decimal and a significant digit DO count.

​498.00

​

​

​4 sig figs!

​5 sig figs!

​3 sig figs!

​ 79.0

​2.000

Rule #3

Zeroes between significant figures DO count

​409

​

​

​5 sig figs!

​3 sig figs!

​4 sig figs!

​7006

​20004

Rule #4

Zeroes at the end of a whole number DO NOT count.

​400

​

​

​1 sig fig!

​1 sig fig!

​2 sig figs!

​7500

​20

Rule #5

Zeroes in front of a number as placeholders DO NOT count.

0.004

​

​

​2 sig figs!

​1 sig fig!

​4 sig figs!

​0.07500

​0.20

Multiple Choice

How many significant figures?

7945

• 1

• 2

• 3

• 4

Multiple Choice

How many significant figures?

0.150

• 1

• 2

• 3

• 4

Multiple Choice

How many significant figures?

76400.0

• 3

• 4

• 5

• 6

Multiple Choice

How many significant figures?

76490

• 3

• 4

• 5

• 6

Sig figs when adding/subtracting

When adding or subtracting, round your answer to the same place as the number with the LEAST amount of DECIMALS.

​45.879 + 32.1 = 77.979

​45.879 + 32.1 = 77.979​ ------> 78.0

​5.41 + 65.456 = 70.866

​​5.41 + 65.456 = 70.866 -------> 70.87

Multiple Choice

Which one is rounded correctly for the following equation?

1.987 - 0.48 = ?

• 1.5

• 1.51

• 1.507

• 2

​Sig figs when multiplying/dividing

When multiplying or dividing, round your answer to the same place as the number with the LEAST amount of SIGNIFICANT FIGURES.

​47.06 x 1.0004 = 47.078824

​​47.06 x 1.0004 = 47.08

​98.04​ = 32.68

3​

​​98.04​ = 30

3​

Multiple Choice

Which one is rounded to the correct number of significant figures for the following equation?

7520 x 0.021 = 157.92

• 157.92

• 157.9

• 158

• 160

Multiple Choice

Which answer is rounded to the correct place for the equation below?

457.1 + 459.32 = 916.42

• 916.42

• 916.4

• 916.0

• 916

Multiple Choice

Which answer is rounded to the correct place for the equation below?

487.0 / .0024 = 121750.0

• 121750.0

• 121800

• 122000

• 120000