Lesson 4 of 11
Where a digit sits decides what it is worth
Show on a big screenThe digits 2, 0 and 5 can write 205. They can also write 502. The two numbers differ by 297. A digit is one of 0 to 9. Why do the same digits make two numbers?
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Step 1 of 4
- Three columns: hundreds, tens, ones.
- A 5 in the ones is worth 5.
- The same 5 in the tens is worth 50.
- The same 5 in the hundreds is worth 500.
Each digit is worth what its column says. A column is the place for one digit. The ones column is worth 1. The tens column is worth 10. The hundreds column is worth 100.
Rule: Each column is worth ten of the column on its right. The digit stays the same.
So 205 is 2 hundreds and 5 ones. That is 200 + 0 + 5.
| Arrangement | Worth | Number |
|---|---|---|
| 205 | 2×100 + 0×10 + 5×1 | 205 |
| 502 | 5×100 + 0×10 + 2×1 | 502 |
Try the lab to finish this lesson.