Ana! At least you did not put "in words please, not by a link." this time.
It is obvious that you have never needed or know anyone who has needed to ask for some help even though they are working and doing the best they can. Which is great but anyone who has or who has helped someone who has will know it is not something you can easily simplify.
This, as I think someone has said above, equates to a household income of about £16,000 pa, or £1,333 a month or £307.69 a week. If you stop to think it is pretty obvious that this is the household income before benefits as the benefits which are added will depend on the composition of the household. It is taken from the Child Poverty Act which underpinned the existing framework and had all party support until IDS decided he knew better.