3.1 Practising dividing fractions
You now know that to divide by a fraction, you convert the second fraction (the one you are dividing by) into its reciprocal, then multiply by that fraction instead.
Just once more, consider .
If you swap the numerator and the denominator of , you will have : this is the reciprocal of .
Thus,
So, dividing a number by is the same as multiplying the number by .
This process of finding the reciprocal of the fraction that appears after the division sign, and then multiplying by that value, can be used in any division problem.
Take the example below.
Aman wants to know how fast she was driving. She drove of a mile in half a minute. To work out speed, you need to divide distance by time. Therefore you can work out how fast she was driving by doing divided by . Using the rule for dividing fractions, that means . So, Aman was driving at or per minute.
Now you are going to look at dividing mixed numbers and fractions.