Mada za sehemu hiiUse ordering skills to solve puzzles in everyday lifeMada 4
- Compare fractions by using =, <, and > signs
- Multiplication and division of fractions
- Explain the concept of decimals
- Addition and subtraction of decimals
Decimals are numbers that have a whole number part and a fractional part, separated by a dot called the decimal point. The decimal point is like a wall that separates the ones, tens, and hundreds from the tenths, hundredths, and thousandths.
The Decimal Point
The decimal point (.) separates the whole number from the fraction. The numbers to the left of the decimal point are whole numbers. The numbers to the right of the decimal point are parts of a whole.
When we write 0.5, the digit 0 is the whole number and 5 is the fractional part. When we write 2.75, the digit 2 is the whole number and 75 is the fractional part.
Tenths
Imagine a shape divided into 10 equal parts. One part is of the whole. In decimal form, we write this as 0.1.
Look at the table below:
| Fraction | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Decimal | 0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 |
Each decimal place to the right of the decimal point is divided by 10.
Hundredths
Now imagine a shape divided into 100 equal parts. One part is of the whole. In decimal form, we write this as 0.01.
Here are more examples from the diagram:
Thousandths
For even smaller parts, we use thousandths. One part out of 1000 is , written as 0.001.
Examples:
Decimals are read from left to right. The digits to the left of the decimal point are read as a whole number. The digits to the right of the decimal point are read one by one.
Worked Example
Read the decimal number 25.6.
Solution
- The whole number part is 25 → read as "twenty-five"
- The decimal point → read as "point"
- The digit 6 → read as "six"
So, 25.6 is read as "twenty-five point six".
More Examples
| Decimal number | How to read it |
|---|---|
| 0.7 | zero point seven |
| 1.8 | one point eight |
| 0.05 | zero point zero five |
| 15.34 | fifteen point three four |
| 131.026 | one hundred and thirty-one point zero two six |
Writing Decimals in Words
Worked Example
Write 13.26 in words.
Solution
13 is read as "thirteen" 26 is read as "two six"
So, 13.26 is written as "thirteen point two six".
Writing Words in Decimals
Worked Example
Write "eleven point six" in numerals.
Solution
Eleven → 11 Six → 6
So, "eleven point six" is written as 11.6.
- The decimal point separates the whole number from the fractional part.
- The first place to the right of the decimal point is tenths (divide by 10).
- The second place to the right is hundredths (divide by 100).
- The third place to the right is thousandths (divide by 1000).
- When reading decimals, say each digit on the right side separately.
- Decimals are obtained by dividing the numerator by the denominator of a fraction (for example, ).
In Tanzania, decimals are used every day when shopping at the market or using mobile money. For example, if you buy 2.5 kilograms of rice at the market, the seller uses decimals to measure the weight. Similarly, when you check your M-Pesa balance or recharge airtime with Tsh 500.50, decimals help show the exact amount. Decimals are also used when measuring medicine doses, reading your weight at the clinic, or checking fuel prices at the petrol station.
Swali
What is a decimal number?
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