GoalName unit fractions and other fractions of shapes and groups, and say how many equal parts make a whole.
New words
fraction · a number that names equal parts of a wholeunit fraction · a fraction with 1 on top, such as 1/3set · a group of things
Explanation
A fraction names equal parts of a whole. The bottom number tells how many equal parts the whole is cut into. The top number tells how many of those parts we are talking about. A fraction with 1 on top, such as 1/2, 1/3 or 1/4, is a unit fraction because it names one equal part. If a bar is cut into 4 equal parts and 3 parts are shaded, the shaded fraction is 3/4. Fractions can also name part of a group. To find 1/4 of 8 birds, share the 8 birds into 4 equal groups. There are 2 birds in each group, so 1/4 of 8 is 2. It takes 2 halves, 3 thirds or 4 fourths to make a whole.
Worked examples
The bar has 4 equal parts and 3 are shaded. The shaded fraction is 3/4. The part that is not shaded is 1/4, a unit fraction.
Find 1/4 of 8 birds. Share the birds into 4 equal groups. There are 2 birds in each group, so 1/4 of 8 is 2.
Fraction of a group
Answer
1/2 of 10
5
1/3 of 9
3
1/4 of 12
3
Fractions of a group: 1/2 of 10 is 5, 1/3 of 9 is 3 and 1/4 of 12 is 3. Check: 2 × 5 = 10, 3 × 3 = 9 and 4 × 3 = 12.
Class activity
Counter shares. Take 6 beans or small stones. Share them into 2 equal groups to find 1/2 of 6, then into 3 equal groups to find 1/3 of 6. Then take 8 beans and find 1/4 of 8. Write what you found.
Practice
1
A shape is cut into 6 equal parts and 1 part is shaded. What fraction is shaded?
1/6 is shaded. It is a unit fraction.
2
How many thirds make a whole?
3 thirds make 1 whole.
3
Salma has 14 oranges. She gives away 1/2 of them. How many oranges does she give away?
1/2 of 14 is 14 ÷ 2 = 7 oranges.
4
There are 9 birds on a wall. Find 1/3 of the birds.
Share 9 into 3 equal groups: 9 ÷ 3 = 3. So 1/3 of 9 is 3 birds.
5
A shape has 8 equal parts and 3 of them are shaded. What fraction is shaded?
