What fraction is the yellow piece?
Grade: Grade 3 · Subject: Math · Time needed: 20 minutes
This is guided discovery. You never tell your child the answer. You ask questions and use real pieces of paper so they work it out and it truly sticks, the way a great tutor teaches.
What your child should already know
- A fraction is an equal part of a whole
- How to count how many pieces make a whole
The idea, explained for you (the parent)
The goal is for your child to discover, by themselves, that the bottom number of a fraction tells you how many equal copies of a piece it takes to fill the whole. You will not say that sentence. You will let them find it by cutting, comparing and cutting up pieces of paper.
Step-by-step session (20 minutes)
- (4 min) Cut a paper square into four pieces: one big piece that is half the square, plus three smaller equal pieces. Color one small piece yellow. Lay them out and ask: "What fraction of the whole square is the yellow piece?"
- (5 min) The likely wrong answer is "one third" (they can see three small pieces). Do not correct it. Instead ask: "You said the yellow piece is a third. What about that big piece, is it also a third?" Let them notice the big piece is far bigger than the small ones. Ask: "Can all the pieces be thirds if they are different sizes?" Guide them to say the rule themselves: the pieces have to be equal.
- (5 min) Hand them the scissors: "Can you cut the big piece so every piece is the same size?" Now the square is four equal pieces. Ask again: "So now, what fraction is the yellow piece?"
- (4 min) Find the bottom number by discovery, not by telling: "How many copies of the yellow piece would it take to fill the whole square?" Have them physically lay copies down and count. Four. "So the bottom number is...?" Let them say it. Write 1/4 together.
- (2 min) Check it truly clicked: "Explain to me, in your own words, why the bottom number is four." If they can say it, it has landed. If not, lay the copies out again together.
Quick practice questions
- A cake is cut into 4 equal pieces. What fraction is one piece?
- It takes 8 equal copies of a piece to fill a whole shape. What is the bottom number?
- A ribbon is cut into 3 equal parts. What fraction is one part?
- Two pieces are different sizes. Can you call them halves? Why or why not?
How to tell it clicked
- Before naming any fraction, your child checks that the pieces are equal
- They find the bottom number by working out how many copies fill the whole, not by counting the pieces they happen to see
If they're stuck
- Go back to real pieces they can physically lay on top of each other
- Ask "how many of THIS piece make the whole?" and count together, slowly
Answers
- 1/4
- 8
- 1/3
- No. Halves must be two equal pieces. Different-sized pieces are not halves.