New
New
Year 7

Checking and securing dividing a fraction by a whole number

I can use the mathematical structures that underpin the division of fractions to divide a fraction by a whole number.

New
New
Year 7

Checking and securing dividing a fraction by a whole number

I can use the mathematical structures that underpin the division of fractions to divide a fraction by a whole number.

Lesson details

Key learning points

  1. A diagram can help to show the underlying structure.
  2. A fraction can be converted to an equivalent fraction.
  3. Equivalent fractions can make the division easier.

Common misconception

When dividing a fraction by an integer, some divide the numerator and denominator by the integer.

Embed the understanding that when dividing by an integer, only the numerator is divided as the number of equal parts remains the same.

Keywords

  • Lowest common multiple - The lowest common multiple is the lowest number that is a multiple of two or more numbers.

On MWBs, give the class 3/5 and ask for as many equivalent fractions where the numerator is divisible by 2. There are an infinite number of equivalent fractions. Why is the LCM best to use? Extend with 2/11 and asking for a numerator divisible by 3.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
Dividing a cake into 4 equal parts means each part represents .
a third
a half
Correct answer: a quarter
a tenth
Q2.
What is the lowest common multiple of 2 and 3?
1
2
Correct answer: 6
12
18
Q3.
What is the lowest common multiple of 5 and 4?
1
4
5
Correct answer: 20
40
Q4.
What is the lowest common multiple of 4 and 12?
1
2
4
Correct answer: 12
48
Q5.
Match the simplified fraction on the left with an equivalent fraction.
Correct Answer:$${1} \over {2}$$ ,$${3} \over {6}$$ 

$${3} \over {6}$$ 

Correct Answer:$${4} \over {5}$$ ,$${12} \over {15}$$ 

$${12} \over {15}$$ 

Correct Answer:$${3} \over {7}$$ ,$${9} \over {21}$$ 

$${9} \over {21}$$ 

Correct Answer:$${1} \over {4}$$ ,$${2} \over {8}$$ 

$${2} \over {8}$$ 

Q6.
What is a half of a half?
A double half
Two halves make a whole
Correct answer: A quarter
A third

6 Questions

Q1.
A pizza is split into 15 equal pieces. A teacher takes 1 piece and the remaining is shared equally between 2 students. What fraction of the whole pizza does each student receive?
Correct answer: $${7} \over {15}$$ 
$${7} \over {14}$$ 
$${1} \over {2}$$ 
$${7.5} \over {15}$$ 
Q2.
A chocolate bar has 17 equal pieces. The teacher eats 7 pieces and shares the rest between 5 students. What fraction of the whole chocolate bar does each student have?
$${5} \over {17}$$ 
Correct answer: $${2} \over {17}$$ 
$${5} \over {10}$$ 
$${1} \over {2}$$ 
Q3.
Work out $$\frac{5}{11} \div5$$.
$$\frac{1}{2/2} $$
$$\frac{1}{6} $$
$$5$$
Correct answer: $$\frac{1}{11} $$
Q4.
Work out $$\frac{12}{17} \div3$$.
$$\frac{4}{5.2} $$
$$4$$
Correct answer: $$\frac{4}{17} $$
Impossible.
Q5.
Match the division on the left with the answer on the right.
Correct Answer:$$\frac{18}{19} \div3$$,$$\frac{6}{19}$$

$$\frac{6}{19}$$

Correct Answer:$$\frac{18}{19} \div6$$,$$\frac{3}{19}$$

$$\frac{3}{19}$$

Correct Answer:$$\frac{18}{19} \div2$$,$$\frac{9}{19}$$

$$\frac{9}{19}$$

Correct Answer:$$\frac{18}{19} \div18$$,$$\frac{1}{19}$$

$$\frac{1}{19}$$

Q6.
Match the question with the answer. Match the division on the left with the answer on the right.
Correct Answer:$$\frac{2}{9} \div3$$,$$\frac{2}{27}$$

$$\frac{2}{27}$$

Correct Answer:$$\frac{3}{9} \div3$$,$$\frac{1}{9}$$

$$\frac{1}{9}$$

Correct Answer:$$\frac{4}{9} \div3$$,$$\frac{4}{27}$$

$$\frac{4}{27}$$

Correct Answer:$$\frac{1}{18} \div3$$,$$\frac{1}{54}$$

$$\frac{1}{54}$$