Roger knows how many keys a piano has. He knows that some of the keys are broken. How can he find the number of keys that work?
Subtract the number of broken keys from the total number of keys.
To find the number of keys that work on a piano, Roger could follow these steps:
1. Count the total number of keys on the piano. Typically, pianos have 88 keys, but there are variations, so it's best to count them all to be accurate. Each key usually corresponds to a musical note.
2. Inspect the keys visually, looking for physical damage or signs of being stuck or unresponsive. It's important to note that physical damage doesn't necessarily mean the key won't work. Some keys might be chipped or have broken tops while still being functional.
3. Test each key individually by pressing it and listening for a sound. Start from the lowest key (usually A0 or C1) and work your way up to the highest key (usually C8). If you hear a clear sound from each key and it feels responsive, mark it as a working key.
4. If a key produces no sound or feels unresponsive, it is likely broken or in need of repair. Note down any non-functional keys.
5. Finally, count the number of keys that are marked as working. This will give you the total number of keys that work on the piano.
It is important to keep in mind that if Roger is not familiar with pianos or lacks the necessary expertise, it would be best to consult a professional tuner or technician who can assess the condition of the keys and make any necessary repairs.