Lesson 6 of 15
Two names for one number
Show on a big screenA sheet has 100 squares. You shade 25. What part is shaded?
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The rule
25 of the 100 squares are shaded. That part is 25/100. It is also 0.25, or 1/4.
The column name is already a fraction. The tenths column has parts of size 1/10. So 0.3 is 3/10.
The hundredths column has parts of size 1/100. So 0.25 is 25/100.
Divide the top and bottom by the same number. The amount stays the same.
Example: 25 ÷ 25 = 1 and 100 ÷ 25 = 4. So 25/100 = 1/4. The simplest name has the smallest top and bottom.
| Decimal | Straight from the column | Divide top and bottom by | Simplest name |
|---|---|---|---|
| 0.5 | 5/10 | 5 | 1/2 |
| 0.25 | 25/100 | 25 | 1/4 |
| 0.75 | 75/100 | 25 | 3/4 |
| 0.2 | 2/10 | 2 | 1/5 |
| 0.125 | 125/1000 | 125 | 1/8 |
A hundred squares cannot show 1/8. That needs 12.5 squares. Use thousandths instead: 125 out of 1000.
Try the lab to finish this lesson.