If you trade your USD for other currencies and the value of the dollar goes down against those currencies your get more dollars when you sell those other currencies for dollars. Thus this means that the value of the other currencies went up.
You get around 100 Rubles for every US dollar let’s say you buy 1000 Rubles with 10 dollars, if the value of the dollar goes to 50 Rubles (meaning the value of the Rubles went up) then you trade those 1000 Rubles back to dollars you’d get 20 US dollars.
If you trade your USD for other currencies and the value of the dollar goes down against those currencies your get more dollars when you sell those other currencies for dollars. Thus this means that the value of the other currencies went up.
You get around 100 Rubles for every US dollar let’s say you buy 1000 Rubles with 10 dollars, if the value of the dollar goes to 50 Rubles (meaning the value of the Rubles went up) then you trade those 1000 Rubles back to dollars you’d get 20 US dollars.
I think it is a good idea to help them to understand to use their language.
The rubles don’t go “up” but the dollar goes “down”.
That better matches their understanding of reality and it is irrelevant for what you try to communicate.