Suresh goes to a shop in Delhi and buys a pencil for Rs 5.50. His mother gives him a Rs 10 note. The shopkeeper returns Rs 4.50. What does the dot (.) in Rs 5.50 mean?
The dot is called a decimal point. The number before the dot shows whole rupees (5 rupees), and the number after the dot shows paise (50 paise). Decimals help us write numbers that are between two whole numbers.
What is a Decimal?
A decimal is a number that has a whole part and a fractional part, separated by a decimal point (.).
In the number 3.7, the whole part is 3 and the fractional part is 7 tenths.
Decimals and Fractions -- They Are Related!
When we divide 1 whole into 10 equal parts, each part is called one-tenth. We write it as 1/10 or 0.1.
When we divide 1 whole into 100 equal parts, each part is called one-hundredth. We write it as 1/100 or 0.01.
| Fraction | Decimal | We Say |
|---|---|---|
| 1/10 | 0.1 | One-tenth |
| 3/10 | 0.3 | Three-tenths |
| 7/10 | 0.7 | Seven-tenths |
| 1/100 | 0.01 | One-hundredth |
| 25/100 | 0.25 | Twenty-five hundredths |
Place Value in Decimals
Let us look at the number 24.63:
| Tens | Ones | . (Decimal Point) | Tenths | Hundredths |
|---|---|---|---|---|
| 2 | 4 | . | 6 | 3 |
The digit 2 is in the tens place (value = 20). The digit 4 is in the ones place (value = 4). The digit 6 is in the tenths place (value = 6/10 = 0.6). The digit 3 is in the hundredths place (value = 3/100 = 0.03).
Reading Decimal Numbers
We read 24.63 as "twenty-four point six three" (not "twenty-four point sixty-three").
We read 7.5 as "seven point five." We read 0.08 as "zero point zero eight."
Comparing Decimals
To compare decimals, first compare the whole number part. If they are the same, compare the tenths. If those are also the same, compare the hundredths.
Example: 3.8 and 3.5 -- whole parts are the same (3 = 3). Compare tenths: 8 > 5. So 3.8 > 3.5.
Write 4/10 as a decimal. Since 4/10 means 4 tenths, we write it as 0.4.
Write 35/100 as a decimal. Since 35/100 means 35 hundredths, we write it as 0.35.
In the number 18.47, what is the place value of 4?
The digit 4 is in the tenths place. Its value is 4/10 = 0.4.
Asha has Rs 12.75 and Deepa has Rs 12.50. Who has more money?
Whole parts: 12 = 12. Tenths: 7 > 5. So Rs 12.75 > Rs 12.50. Asha has more money.
| Word | Meaning |
|---|---|
| Decimal | A number with a whole part and a fractional part separated by a decimal point |
| Decimal point | The dot (.) that separates the whole part from the fractional part |
| Tenths | The first place after the decimal point (1/10) |
| Hundredths | The second place after the decimal point (1/100) |
| Place value | The value of a digit based on its position in the number |
Finished learning? Now test what you know!