3
Naming the parts
Discover Mathematics P2: Term 2, Lessons 101–110
GoalRead and write fractions such as 1/2, 2/3 and 3/4.
New words
fraction · a number that names part of a wholenumerator · the top number: how many parts we are talking aboutdenominator · the bottom number: how many equal parts in the whole
Explanation
We write a fraction with two numbers and a line. The bottom number tells how many equal parts the whole has. The top number tells how many of those parts we mean. In 1/2, the whole has 2 equal parts and we mean 1 of them: one half. In 2/3 we mean 2 of 3 equal parts: two thirds. In 3/4 we mean 3 of 4 equal parts: three fourths.
Worked examples
Omar ate 3 of the 4 equal pieces of a pizza. The shaded part is 3/4, three fourths.
A ribbon has 3 equal parts and 1 part is coloured. The fraction is 1/3, one third.
A round bread is cut into 3 equal parts and 2 of them are shaded. The fraction is 2/3, two thirds.
Class activity
Fraction cards. Draw four rectangles on paper. Divide them into 2, 3, 4 and 4 equal parts. Colour 1, 2, 3 and 1 parts. Write the fraction under each rectangle and read it aloud. Mix the cards and match each fraction to its picture.
Practice
1
Write the fraction that is shaded.
3/4.
2
Write the fraction that is shaded.
1/2.
3
A fraction has 3 on the bottom and 2 on top. How many equal parts does the whole have? How many are we talking about?
The whole has 3 equal parts and we mean 2 of them.
4
Read the fraction 1/4 in words.
One fourth, or one quarter.
5
Hana colours 2 of the 4 equal parts of a strip. Write the fraction.
2/4.