Checking understanding of addition and subtraction with fractions | Maths

Starter quiz

What is the word for the number above the fraction line?

'numerator' ✓
Which of the following are equivalent to ${2}\over{3}$ ?

${4}\over{6}$ ✓

${8}\over{10}$

${10}\over{15}$ ✓

${14}\over{21}$ ✓

${24}\over{35}$
Calculate ${2}\over{7}$ + ${4}\over{7}$ .

${2}\over{7}$

${3}\over{7}$

${6}\over{7}$ ✓

${8}\over{7}$
Calculate ${6}\over{7}$ - ${3}\over{7}$ .

${1}\over{7}$

${2}\over{7}$

${3}\over{7}$ ✓

${4}\over{7}$
The larger the denominator, the ______ the parts.

'smaller' ✓
Sort the following from smallest to largest.

1

⇔

${1}\over{20}$

2

⇔

${1}\over{13}$

3

⇔

${1}\over{9}$

4

⇔

${1}\over{5}$

5

⇔

${1}\over{3}$

The most efficient way to add or subtract fractions is using the ______.

HCF

LCM ✓

same denominator

doing the same to the top and bottom
Which of the following is not a common denominator of ${1}\over{4}$ and ${7}\over{12}$ ?

2 ✓

12

36

120
$\frac{2}{7} + \frac{1}{8} \square \frac{2}{7} + \frac{1}{9}$

> ✓

<

=
Calculate ${5}\over{12}$ - ${1}\over{4}$ .

${4}\over{8}$

${2}\over{12}$ ✓

${3}\over{12}$

${4}\over{12}$
Which of the following is not a correct alternative for ${1}\over{4}$ - ${5}\over{8}$ + ${3}\over{16}$ ?

${1}\over{4}$ + ${3}\over{16}$ - ${5}\over{8}$

${1}\over{4}$ - $\left(\frac{5}{8} + \frac{3}{16}\right)$ ✓

${1}\over{4}$ + ${3}\over{16}$ + $\left(-\frac{5}{8}\right)$
Calculate ${1}\over{4}$ - ${5}\over{8}$ + ${3}\over{16}$ ?

$\left(-\frac14\right)$

$\left(-\frac2{16}\right)$

$\left(-\frac3{16}\right)$ ✓

$\left(-\frac9{16}\right)$

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The denominators of each fraction should split the whole into the same number of equal pieces.
The numerators are added or subtracted.
The size of each piece has not changed so the denominator does not change.

Simply adding or subtracting the numerators and denominators.

Emphasise that the denominator tells us the name of the unit. In order to add or subtract things they must have a common name.

Numerator - The expression in a fraction that is written above the fraction line. It is the dividend.
Denominator - The expression in a fraction that is written below the fraction line. It is the divisor.
Proper fraction - A proper fraction is a fraction where the numerator is less than the denominator.
Lcm - LCM is an abbreviation for lowest common multiple.