2
Writing numbers two ways
Discover Mathematics P2: Term 1, Lessons 21–30
GoalWrite the same number in standard form, expanded form and in words.
New words
standard form · the number written with digitsexpanded form · the number split into hundreds, tens and onesword form · the number written with words
Explanation
One number can be written in different ways, and all of them mean the same amount. For 348, the standard form is 348. The expanded form is 300 + 40 + 8. The word form is three hundred forty-eight. To change from one way to another, look at each place one by one.
| Standard | Expanded | Words |
|---|---|---|
| 348 | 300 + 40 + 8 | three hundred forty-eight |
Worked examples
Standard to expanded: 417 = 400 + 10 + 7.
Expanded to standard: 600 + 30 + 2 = 632.
| Standard | Expanded | Words |
|---|---|---|
| 257 | 200 + 50 + 7 | two hundred fifty-seven |
Class activity
Chain game. One player says a number in standard form, the next says it in expanded form, and the next says it in words. Keep turning, and use new numbers each round.
Practice
1
Write 507 in expanded form.
500 + 7
2
Write 900 + 80 + 1 as a number.
981
3
Write 125 in words.
one hundred twenty-five
4
Do 200 + 50 + 7 and 250 + 7 make the same number?
Yes. Both make 257.
5
Which one is not 483: 400 + 80 + 3, 400 + 30 + 8 or 480 + 3?
400 + 30 + 8, because it makes 438.