Decimal fractions are a special way of representing parts of a whole where the denominator is a power of 10, such as 10, 100, or 1000. Instead of using a fraction bar, we use a decimal point to separate the whole number from the fractional part.
To understand decimal fractions, we must look at the place value system. When we move to the right of the units place, we use a dot called the decimal point.
| Tens | Units | Decimal Point | Tenths (1/10) | Hundredths (1/100) |
|---|---|---|---|---|
| 1 | 5 | . | 7 | 5 |
A fraction like 5/10 is written as 0.5 and read as "zero point five". If we have a mixed fraction like 3 and 4/10, it is written as 3.4.
When adding or subtracting decimal fractions, always line up the decimal points vertically.
To quickly convert a fraction with a denominator of 100 to a decimal, count two places from the right and place the decimal point. For example, 45/100 becomes 0.45.
Students often forget to align the decimal points during subtraction, leading to incorrect calculations. Always add placeholder zeros if the number of digits after the decimal differs.
Decimal fractions use a decimal point. The first place to the right is tenths, and the second is hundredths. Always align the point for addition and subtraction.