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Year 3

Add and subtract fractions with the same denominator in a range of contexts

I can add and subtract fractions with the same denominator in a range of contexts.

Download all resources
Share activities with pupils
New
New
Year 3

Add and subtract fractions with the same denominator in a range of contexts

I can add and subtract fractions with the same denominator in a range of contexts.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. If fractions have the same denominator they can be added or subtracted.
  2. Number lines can represent addition and subtraction of fractions with the same denominator.
  3. When you add or subtract fractions with the same denominator you add or subtract the numerators.

Common misconception

Children might still try to add or subtract the denominators as well due to a misunderstanding about the denominator showing what unit-fraction is being used for calculation.

By this stage, buddy checking can be useful. Get the children to check each other periodically but ensure that children can also explain why this is incorrect.

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.

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 subtrahend?
Correct answer: A number subtracted from another number.
The number being subtracted from.
The result after subtracting one number from another.
Q2.
Which number is the minuend in the following equation? 14 − 6 = 8
Correct answer: 14
6
8
Q3.
What addition is being shown by this number line?
An image in a quiz
30 = 20 + 50
50 + 30 = 20
Correct answer: 30 + 20 = 50
30 + 50 = 20
Q4.
Each marble in a bag is $$ \frac{1}{10} $$ of the whole bag. How many marbles are there in the bag?
1
Correct answer: 10
12
13
Q5.
The bar model shows four equal parts of the whole. What fraction can be used to label this?
An image in a quiz
$$ \frac{1}{2} $$
$$ \frac{1}{3} $$
Correct answer: $$ \frac{1}{4} $$
Q6.
Select the correct sum. $$ \frac{2}{12} $$ + $$ \frac{7}{12} $$ = ___
Correct answer: $$ \frac{9}{12} $$
$$ \frac{5}{12} $$
$$ \frac{9}{24} $$
$$ \frac{14}{12} $$

Exit quiz

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6 Questions

Q1.
Choose the correct ending for this sentence. When adding or subtracting fractions with the same denominator, __________
add the numerators and add the denominators.
Correct answer: the denominator stays the same and the numerators are used for the calculations.
Q2.
$$ \frac{4}{10} $$ + $$ \frac{5}{10} $$ − $$ \frac{3}{10} $$ = ___
$$ \frac{5}{10} $$
Correct answer: $$ \frac{6}{10} $$
$$ \frac{7}{10} $$
$$ \frac{8}{10} $$
Q3.
Laura had a water bottle that was $$ \frac{9}{10} $$full. She drank $$ \frac{4}{10} $$ of the bottle and then topped it up by $$ \frac{2}{10} $$ What will the denominator of your answer be?
Correct Answer: 10
Q4.
Laura had a water bottle that was $$ \frac{9}{10} $$ full. She drank $$ \frac{4}{10} $$ of the bottle and then topped the bottle up by $$ \frac{2}{10} $$ How much water is left in the bottle?
$$ \frac{9}{10} $$
$$ \frac{5}{10} $$
Correct answer: $$ \frac{7}{10} $$
$$ \frac{7}{20} $$
Q5.
Sam is making juice. First, she adds in $$ \frac{10}{15} $$ of apple juice. Then, she adds in $$ \frac{3}{15} $$ of orange juice and pours out $$ \frac{9}{15} $$ of the mix. What fraction is left?
$$ \frac{3}{15} $$
Correct answer: $$ \frac{4}{15} $$
$$ \frac{5}{15} $$
Q6.
Which expressions have a total greater than $$ \frac{5}{12} $$?
Correct answer: $$ \frac{9}{12} $$ − $$ \frac{3}{12} $$
$$ \frac{2}{12} $$ + $$ \frac{3}{12} $$
Correct answer: $$ \frac{3}{12} $$ + $$ \frac{4}{12} $$
$$ \frac{8}{12} $$ − $$ \frac{4}{12} $$