You know halves and fourths. Thirds are new.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
Cut a whole into 3 equal shares.
Third is one of three equal shares of a whole.
Between a half and a fourth
A third is smaller than a half but bigger than a fourth.
Three thirds make one whole, just as two halves do.
Three equal shares
Cutting a whole into three equal parts gives thirds. One of those parts is one third. Three thirds make the whole again, in the same way two halves do.
A third is smaller than a half
The more shares you cut a whole into, the smaller each share must be. So a third is smaller than a half, even though 3 is bigger than 2. This feels backwards at first and it is the most important idea in this whole chapter.
Why thirds are harder to cut
You can make halves by folding a strip once and fourths by folding twice. There is no folding trick for thirds — you have to judge it. That is a nice reminder that halving repeatedly gives 2, 4, 8 parts, but never 3.
Step 2: Try It Yourself
Set it to 3 shares and read the name.
The whole is cut into 3 equal shares, called thirds.
The whole is cut into 3 equal shares, called thirds.
Step 3: Watch an Example
One step at a time.
Watch Leo Cut Thirds
Leo shares a chocolate bar between 3 people.
- Step 1
He makes two cuts, not three, to get three pieces.
Step 4: Your Turn
Practice makes it stick.
Three Friends
Problem 1 of 2
A pizza is shared equally between 3 friends. What is each share called?
Which Is Bigger
Problem 2 of 2
Which is bigger, a third or a fourth?
Thirds
1 of 3
How many thirds make one whole?
2 of 3
How many cuts make three equal pieces of a bar?
3 of 3
Which is smallest?
Step 5: Quick Check
Show what you know.
Question 1 of 2
How many thirds make one whole?
Question 2 of 2
Which is bigger, a half or a third?
What You Learned
- Three equal shares are called thirds.
- Three thirds make one whole.
- A third is smaller than a half and bigger than a fourth.