Family I · What fractions describe
Parts & Wholes
These lessons are about what a fraction actually describes: equal shares of a whole, and what the top and bottom numbers are counting. Every other fraction idea rests on them, so this is a good place to start if things feel shaky.
- Slice 01
Equal Means Equal
Do the parts of a fraction have to be equal?
Sounds like “I cut it into four pieces, so each piece is a fourth.”
The big idea Fourths have to be four equal parts of one whole. The parts can be different shapes, as long as they’re all the same size.
- Slice 02
What’s the Whole?
Is half of a large pizza the same amount as half of a small pizza?
Sounds like “Half is half. My half of the little pizza is the same as your half of the big one.”
The big idea A fraction is always part of a particular whole, so the same fraction of a bigger whole is a bigger amount.
- Slice 03
The Bottom Number
What does the bottom number of a fraction mean?
Sounds like “One piece is shaded and four aren’t, so that’s (one fourth).”
The big idea The bottom number tells you how many equal parts make one whole, so it counts every part, whether it’s shaded or not.
- Slice 04
The Top Number
What does the top number of a fraction mean?
Sounds like “The top number is how many pieces there are altogether.”
The big idea The top number counts how many of the equal parts you have, so (three fifths) means you have 3 of the 5 equal parts.
- Slice 05
Fractions of Collections
What is (one fourth) of 12?
Sounds like “(one fourth) of 12 counters is 1 counter. It says 1.”
The big idea A whole can be a group of things, so (one fourth) of 12 counters is one of 4 equal groups, which is 3 counters.