One of the reasons I got into design engineering was Family. The first time I used the app I was blown away by the attention to detail and the user experience. I decided to re-create a couple of the components from the app on the web.
Currency Converter
The number animation in this component uses Number Flow and shared layout animations from Motion. The text formatting is handled using react-number-format.
The Use Max / Using Max transition is done by splitting the words into individual spans and animating them using Motion. Thanks to Janum Trivedi for the tip regarding the transition. Adding an x translate made a pretty big difference in how the interaction feels.