Decimal Places and Significant Figures

Flashcards covering key concepts on decimal places and significant figures.

Decimal Places (d.p)

The number of digits to the right of the decimal point in a number.

Tenths

One part of a whole divided into ten equal parts, represented as 1/10.

Hundredths

One part of a whole divided into one hundred equal parts, represented as 1/100.

Thousandths

One part of a whole divided into one thousand equal parts, represented as 1/1000.

Rounding Rule for Decimal Places

To round a number, look at the digit to the right of the desired decimal place; if it's 5 or greater, round up, otherwise round down.

Significant Figures (s.f)

Digits in a number that carry meaningful information about its precision.

Most Significant Figure

The left-most digit in a number, which is the first non-zero digit.

Least Significant Figure

The right-most digit in a number, which usually provides the least precision.

Rounding Rule for Significant Figures

To round to significant figures, identify the first non-zero digit and follow standard rounding rules.

Non-Zero Significant Figures

All non-zero digits are counted as significant figures.

Zeroes Between Significant Figures

Zeros located between non-zero digits are considered significant.

Trailing Zeros

Trailing zeros in a number are significant only when there is a decimal point.

Example of Rounding to Two Decimal Places

To round 4.708712 to two decimal places, the result is 4.71.

Multiplying Decimals by Powers of Ten

When multiplying by 10, 100, etc., move the decimal point to the right.

Dividing Decimals by Powers of Ten

When dividing by 10, 100, etc., move the decimal point to the left.

Expressing 306.96 to One Decimal Place

The result of expressing 306.96 to one decimal place is 307.

Example of Significant Figures: 7218

Rounded to 2 significant figures is 730.

Example of Non-Zero Count in Significant Figures: 123456

The number has six significant figures.

Exponentially Large Numbers with Significant Figures

The number 6000000000000002 has 16 significant figures.

Example of Trailing Zeroes: 120000

Has two significant figures if no decimal is shown.