why do you multiply fractions instead of dividing? cause my teacher always said to invert and multiply and i was confused why.
+9466 It is easier to multiply fractions.
For example:
\(\frac34\div\frac57=\frac34\,*\,\frac75\)
Then, just multiply straight across.
\(=\frac{3*7}{4*5}=\frac{21}{20}\)
It is true that
\(\frac34\div\frac57=\frac{3\div5}{4\div7}=\frac{21}{20}\)
But how are you going to evaluate 3 / 5 and 4 / 7 without using a calculator or long division?
And...to see why inverting and multiplying is the same as dividing, take a simple example:
\(10\div2=10\,*\,\frac12=\frac{10}{1}\,*\,\frac12=\frac{10}{2}\)
+9466 It is easier to multiply fractions.
For example:
\(\frac34\div\frac57=\frac34\,*\,\frac75\)
Then, just multiply straight across.
\(=\frac{3*7}{4*5}=\frac{21}{20}\)
It is true that
\(\frac34\div\frac57=\frac{3\div5}{4\div7}=\frac{21}{20}\)
But how are you going to evaluate 3 / 5 and 4 / 7 without using a calculator or long division?
And...to see why inverting and multiplying is the same as dividing, take a simple example:
\(10\div2=10\,*\,\frac12=\frac{10}{1}\,*\,\frac12=\frac{10}{2}\)
