Idea 1of 23
A digit is worth its place
What is a digit worth in a big number?
Today you'll discover
- the names of the five places
- what each digit is worth
- why moving a digit changes its value
Think first42 315 in a place-value chart
In 42 315, what is the 4 worth?
Decide first, then press Next. Read the heading above the digit.
A place-value chart with columns for ten thousands, thousands, hundreds, tens and ones holding 4, 2, 3, 1 and 5, the 4 outlined. Then each digit's value under it: 40 000, 2 000, 300, 10 and 5, and their sum, 42 315. Curved arrows marked times 10 join each place to the one on its left. The last step asks about the 6 in 86 091.
See the whole ideathe big idea and the key word, in one place
The big idea
A digit is worth the digit times its place: the 4 in 42 315 is worth 40 000.
The five places
From the left: ten thousands, thousands, hundreds, tens, ones.
- ten thousands40 000
- thousands2 000
- hundreds300
- tens10
- ones5
For exampleBig numbers are all around: the people in a town, the kilometres on a car, the seats in an arena, the steps in a school's walkathon.
Key word
- place value
- what a digit is worth because of the place it sits in
Ready to use it?
- Say what a digit is worth from the place it sits in.