Batteries age by charge cycles, not by months. A phone holding 78% of its original charge is not broken — just older. The figure only falls.
The drawing that proves the sentence above. It is the same card that is in the book.
Think of it as
a bucket that has slowly sprung leaks.
For example
Your three-year-old phone needs charging by dinnertime. It is not broken. The bucket simply holds less water than it used to.
This is one card out of 275.
The hundred words you meet most are free — the whole set, animated, in one file that works with no internet.
Volume 1 has all 275 in fifteen chapters, with Staying Safe the largest chapter on purpose.