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Year 3

Subtract fractions with the same denominator

I can subtract fractions with the same denominator.

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New
New
Year 3

Subtract fractions with the same denominator

I can subtract fractions with the same denominator.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. If 5 subtract 2 is equal to 3 then 5 one sevenths subtract 2 one sevenths is equal to 3 one sevenths.
  2. To subtract fractions with the same denominator you subtract the numerators using the language of unitising.
  3. If fractions have the same denominator they can be subtracted.

Common misconception

Children will rush to subtract both the numerator and the denominator when performing a subtraction of fractions with either structure in the lesson.

Reinforce the concept of the unit being the fraction which is denoted by the denominator. Get children to perform subtractions using real life objects before moving them onto using fractions instead, perhaps using unit fractions to begin with.

Keywords

  • Minuend - The minuend is the number being subtracted from.

  • Subtrahend - A subtrahend is a number subtracted from another. There can be more than one.

  • Numerator - A numerator is the top number in a fraction. It shows how many parts we have.

  • Denominator - A denominator is the bottom number in a fraction. It shows how many parts a whole has been divided into.

These structure should be very familiar to the children. It's not the complexity of the subtraction structure but the use of fractions that makes the concepts more challenging.
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).

Video

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Starter quiz

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6 Questions

Q1.
Which of these definitions describes the minuend?
A number subtracted from another number.
Correct answer: The number being subtracted from.
The result after subtracting one number from another.
Q2.
Which number is the subtrahend in the following equation? 12 − 5 = 7
12
Correct answer: 5
7
Q3.
What subtraction is being shown by this number line?
An image in a quiz
Correct answer: 30 = 60 − 30
Correct answer: 60 − 30 = 30
30 − 60 = 30
60 − 60 = 30
Q4.
Each marble in a bag is $$ \frac{1}{12} $$ of the whole bag. How many marbles are there in the bag?
1
10
Correct answer: 12
13
Q5.
The bar model shows three equal parts of the whole. What fraction can be used to label this?
An image in a quiz
$$ \frac{1}{2} $$
Correct answer: $$ \frac{1}{3} $$
$$ \frac{1}{4} $$
Q6.
Select the correct sum. $$ \frac{3}{9} $$ + $$ \frac{4}{9} $$ = ___
Correct answer: $$ \frac{7}{9} $$
$$ \frac{6}{9} $$
$$ \frac{7}{18} $$
$$ \frac{1}{9} $$

Exit quiz

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6 Questions

Q1.
What fraction subtraction equation is being represented by the bar model?
An image in a quiz
$$ \frac{7}{7} $$ − $$ \frac{3}{7} $$ = $$ \frac{4}{0} $$
$$ \frac{7}{7} $$ − $$ \frac{3}{7} $$ = $$ \frac{4}{14} $$
Correct answer: $$ \frac{7}{7} $$ − $$ \frac{3}{7} $$ = $$ \frac{4}{7} $$
$$ \frac{7}{7} $$ − $$ \frac{3}{7} $$ = 4
Q2.
Aisha and Alex share a pizza cut into 8 slices. Alex eats sixth-eighths of the pizza. How much does Aisha eat? Aisha eats ___ of the pizza.
An image in a quiz
$$ \frac{1}{8} $$
Correct answer: $$ \frac{2}{8} $$
$$ \frac{2}{16} $$
$$ \frac{2}{2} $$
Q3.
A full box of eggs contains 12 eggs. First there were 10 eggs in the box, then 4 were used to make pancakes. Which equation matches this problem?
An image in a quiz
$$ \frac{10}{12} $$ − $$ \frac{4}{12} $$ = $$ \frac{14}{12} $$
Correct answer: $$ \frac{10}{12} $$ − $$ \frac{4}{12} $$ = $$ \frac{6}{12} $$
$$ \frac{10}{12} $$ − $$ \frac{4}{12} $$ = $$ \frac{6}{0} $$
$$ \frac{10}{12} $$ − $$ \frac{4}{12} $$ = $$ \frac{6}{24} $$
Q4.
A full box of eggs contains 12 eggs. First there were 8 eggs in the box, then 7 were used to make pancakes and cakes. Which fraction represents the number of eggs left?
An image in a quiz
$$ \frac{7}{8} $$
$$ \frac{1}{7} $$
$$ \frac{1}{8} $$
Correct answer: $$ \frac{1}{12} $$
Q5.
$$ \frac{11}{12} $$ − $$ \frac{7}{12} $$ = ___
Correct answer: $$ \frac{4}{12} $$
$$ \frac{4}{10} $$
$$ \frac{4}{1} $$
$$ \frac{4}{0} $$
$$ \frac{4}{24} $$
Q6.
$$ \frac{9}{10} $$ − $$ \frac{1}{10} $$ − $$ \frac{5}{10} $$ = ___
Correct answer: $$ \frac{3}{10} $$
$$ \frac{4}{10} $$
$$ \frac{5}{10} $$
$$ \frac{3}{20} $$
$$ \frac{4}{20} $$