Seems to be on trend that Sunak wants to fix the cost of living crisis & the NHS by improving adult numeracy. When you live on a low income the problem is that you're too scared to look at your bank balance! It's not that you don't understand it.
When you live life on a low income it's takes great courage to scrutinise your spending habits or check your finances. At times it's far easier to remain in the dark about what's going on in your bank account & just hope for the best. Obviously something he's never had to think about before.