Imagine you didn’t know what it was priced after the reduction. Use “y” as the original number since we don’t know: y times (1-1/6) = 75
it is 1 minus 1 over 6 since you aren’t finding the price after reduction. Your finding the original one which means you need to minus by one (6 over 6= 1) so u would do 1 - 1/6
So if you do it the other way round it would be 75 divided by 1 minus 1 over 6
Which gives us 90!!