Why Learn Music? Why Learn Maths?

Facebook is filled with random uninvited comments.

2 comments about education that I read were: 

- Why learn music or learn to play the recorder?

- Lesson hours for Additional Maths should be reduced: dy/dx has no application in life

Personally I hated both Music and Add Maths. Super-thankful that for a law/ business qualification I didn't have to revisit either subject. I would have failed helplessly.

However, because I am a fair person, I would like to consider potential answers for these questions:

- Music is useful for us to appreciate the 'back-end' of songs: the musical notes, the instruments, and working together (harmonising); and why the recorder? because it is an affordable instrument, within everyone's budget;

- Add Maths concepts especially are used by people who develop our smart devices (this I paraphrase from the reply below); and anything from construction to automobiles to anything involving distance, speed, and accuracy (these were from Google, because I don't really remember this formula much); and

- Overall, school children should explore all subjects so that we develop interest in maths. science and music (among others); we surely need more girls/ women in science; and more artistic minds.

Below are the screenshots related to the dy/dx (Additional Mathematics) comment & its response:

Below is the screenshot of comment about music/ playing the recorder: