Subtracting Fractions on a Number Line — Let's Practise

Subtracting Fractions on a Number Line — Let's Practise exercise

• Which number is the numerator?

  Hints

  The denominator is the bottom number in a fraction.

  In the fraction $\frac{2}{3}$ , the numerator is 2.

  Solution

  The numerator in the fraction is the 1. The top number is the numerator and it will be very important in subtracting fractions.

• Subtract these fractions and find the solution.

  Hints

  Since the problem is $\frac{7}{10}$ - $\frac{3}{10}$, you should start counting back from the fraction $\frac{7}{10}$.

  The numerator in $\frac{3}{10}$ is 3, so count back 3 from $\frac{7}{10}$.

  Solution

  The correct answer is $\frac{4}{10}$. If you count back 3 points on the number line from $\frac{7}{10}$, you will see the answer is $\frac{4}{10}$.

• Subtract these fractions and find the solution.

  Hints

  Here is the number line you should use to solve the problem.

  Since the problem is $\frac{4}{5}$ - $\frac{2}{5}$, you should start counting back from the fraction $\frac{4}{5}$.

  Count back 2 from $\frac{4}{5}$.

  Solution

  The correct answer is $\mathbf{\frac{2}{5}}$.

  If you count 2 points back on the number line starting at $\frac{4}{5}$, you will see the answer is $\mathbf{\frac{2}{5}}$.

• Can you find the answers to these subtraction problems?

  Hints

  Remember, when subtracting fractions, if the denominators are the same in the problem, the solution is likely to have the same denominator too.

  Have a go at drawing your own number lines to solve these problems.

  When using a number line to subtract, use the numerator (top number) in the second fraction to count backwards.

  Solution

  Here are the correct answers.

• What is the missing numerator?

  Hints

  Here is how your number line should look. Use this to help you solve the problem.

  Start counting down from $\frac{9}{10}$.

  Count back 5 from $\frac{9}{10}$.

  Solution

  $\frac{9}{10}$ - $\frac{5}{10}$ = $\mathbf{\frac{4}{10}}$.

  We are subtracting $\frac{5}{10}$. The numerator is 5, so we count 5 points back on the number line from $\frac{9}{10}$ to get the answer $\frac{4}{10}$.

• What is the missing numerator?

  Hints

  We can use a number line to help us find the missing number, too. Use this number line to help.

  To find the missing number, we just need to find the difference between the numbers we do know. Subtract the smaller fraction from the larger fraction.

  Solution

  The missing number is 4. We found this by subtracting $\frac{7}{8}$ - $\frac{3}{8}$, leaving us with the solution $\frac{4}{8}$.