Answer:
She is wrong and the correct answer is [tex]\frac{5}{21}[/tex].
Step-by-step explanation:
The given expression is
[tex]\frac{4}{7}-\frac{1}{3}[/tex]
Sandra says that [tex]\frac{4}{7}-\frac{1}{3}=\frac{3}{4}[/tex] because all you have to do is subtract the numerators and subtract the denominators.
She is wrong. The correct method is shown below.
Make the denominator common.
[tex]\frac{4\times 3}{7\times 3}-\frac{1\times 7}{3\times 7}[/tex]
[tex]\frac{12}{21}-\frac{7}{21}[/tex]
On further simplification we get
[tex]\frac{12-7}{21}[/tex]
[tex]\frac{5}{21}[/tex]
Therefore, the correct answer is [tex]\frac{5}{21}[/tex].
