Idea 3of 22Builds onA bigger bottom number means a smaller piece
Count in thirds
One third, two thirds, three thirds: what comes next?
Today you'll discover
- how to count in unit fractions
- which number changes as you count
- what happens after one whole
Think firstFour pieces, each one third of a whole
Count these thirds: 1/3, 2/3, 3/3 … what is the fourth?
Decide first, then press Next. Watch which number changes and which stays the same.
Four tinted pieces, each marked 1/3, slide together into bars the width of one whole. They are numbered 1/3, 2/3, 3/3, 4/3. The first bar is full and marked one whole; the fourth piece sits alone at the start of a second, dashed bar. The last step counts five quarters.
See the whole ideathe big idea and the key word, in one place
The big idea
Counting thirds changes only the numerator: 1/3, 2/3, 3/3, 4/3.
The same actionCounting thirds, adding thirds and multiplying thirds all repeat one piece. Each time, the top number counts the pieces.
Key word
- numerator
- the top number of a fraction: how many of the pieces you have
Ready to use it?
- Count on in unit fractions past one whole.