Financial planing 101. I know when I graduated from high school I was completely unprepared to make a budget, plan for expenses or save money.
Having students do financial arithmetic on paper is as helpful and realistic as having them write out essays in cursive handwriting.
It was all concepts and foundational equations like compound interest.
If you're using the fact that this would involve "spreadsheets" as a way to link it it ICT education which is what this thread is about then I don't even know what we're talking about anymore.
That is, emphasize finances (practically, using realistic tools). Covering basics of Finance is probably fine, but only to the extent that they understand the gravity of a 22% compound interest rate. Being able to do complex calculations with that rate is probably less practical than learning some other things, like knowing how buying a piece of property works.
Financial education is WAY more complex than it was 20 years ago, with many more ways for people to go wrong
Typically, kids learn more from the ACTIONS of adults in their lives than WORDS. I may have picked up my simple way of life from my parents when cash was tight but my younger ones who grew up in a more financially relaxed atmosphere are spend thrifts.