I agree the girl math tongue in cheek jokes are not so bad. I am more concerned about the ad saying buying make up is a “guilt free” purchase compared to buying breakfast instead. The message is clear- looking good is so important you should feel guilty if you don’t skip meals to afford makeup.
Or, alternatively, 'eat one breakfast at home and then you can afford it'.
It's playing on the way a lot of financials are contextualised to young people on SM these days - don't buy a coffee in Starbucks every day when you can have coffee at home/in the office, save the £4 and that's almost £1.5K a year. Hell, even on MN people say the same thing to people trying to save, because it makes good financial sense.
It's not saying 'skip meals', but 'you think nothing about dropping £7 on a croissant and a Frappuccino so £7 isn't a bad investment for something that will last a long time, so have toast at home instead'...but that isn't as catchy. The 'guilty pleasure' they're giving up isn't breakfast, it's breakfast 'out'.
I agree the ad is shit, but it's a stretch to say they're encouraging girls not to eat. It also isn't really 'girl math'...