Question

What is the value of `5 1/4 xx 4/9` ?

Answer 1

`7/3`

Explanation:

First change `5 1/4` into an improper fraction.

`5 1/4 = 21/4`

so `" "5 1/2xx4/9" " ->" " 21/4 xx 4/9`

Now let's multiply.

`(21times4)/(4times9)`

`84/36`

Which simplifies to

`21/9 = 7/3`

Answer 2

`7/3`

Explanation:

`5 1/4 xx4/9 " change to improper fractions"`

=`21/4 xx 4/9`

When multiplying fractions, it is usually easier to CANCEL a numerator with a denominator by using any COMMON FACTOR.

Remember `5/5 = 1, " "3/3 = 1" "6/6 = 1` etc

This has the effect of giving us smaller numbers to work with, and if done completely there is no further simplifying necessary after we multiply.

However, cancelling may ONLY be done across/through a multiplication sign.

=`21/cancelcolor(blue)4^1 xx cancelcolor(blue)4^1/9 " divide by 4"`

`cancelcolor(red)21^7/cancel4^1 xx cancel4^1/cancelcolor(red)9^3 " divide by 3"`

=`(7xx1)/(1xx3) = 7/3`