Question

How do you reduce `420/480`?

Answer 1

Please see below.

Explanation:

There are two ways.

(1) The easier way is to identify Greater Common Factor (GCF) of numerator and denominator and then divide numerator and denominator by GCF.

Here GCF of numerator `420` and denominator `480` is `60`, which gives us `420/480=(60xx7)/(60xx8)=7/8`

(2) But if one finds calculating GCF cumbersome, one can also undertake multiple divisions, until there is no common factor between numerator and denominator.

In the given case as `60=2xx2xx3xx5`, one will have to divide twice by `2`, and then once each by `3` and `5`. This way

`420/480=(2xx210)/(2xx240)=210/240`

= `(2xx105)/(2xx120)=105/120`

= `(3xx35)/(3xx40)=35/40`

= `(5xx7)/(5xx8)=7/8`