Fractions with the Same Denominator
Primary 4 · Mathematics
Fractions with the Same Denominator
Lesson 5 of 5
25 min
Let's begin
There is 12 of a loaf of bread left on the table. Mother shares it equally between Keza and Mugisha. How much of the whole loaf does each child get?
We need 12 ÷ 2. Cut the half into 2 equal pieces:
If you cut the other half the same way, the whole loaf would have 4 equal pieces. So each child gets 14 of the loaf: 12 ÷ 2 = 14.
To divide a fraction by a whole number, keep the numerator and multiply the denominator by the whole number.
Dividing by 2 is the same as taking half, and dividing by 3 is the same as taking a third. That is why 12 ÷ 3 is the same as 13 × 12 = 16.
If the numerator can be shared exactly, you can just divide the numerator. 67 ÷ 3: share 6 sevenths among 3 and each gets 27. The rule gives the same answer: 621 = 27.
Tip
Sharing makes smaller pieces. When you divide a fraction by a whole number, the answer is always smaller than the fraction you started with, because the bottom number gets bigger.
Work each one in your exercise book first. Then tap Show answer to check.
13 ÷ 2
Answer: 16
14 ÷ 3
Answer: 112
45 ÷ 2
Answer: 25 (410 simplified, or share the 4 fifths between 2)
34 ÷ 3
Answer: 14
Mother pours 12 litre of milk equally into 4 cups. How much milk is in each cup?
Answer: 18 litre, because 12 ÷ 4 = 18.
What you learned today
Sources and credits
The stories, Rwandan worked examples, diagrams and practice questions were written by Ganzaa.
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