I didn’t find yet the explanation, so I’m post (maybe already exists)

I cut this from a sketch that I found on the internet, but, I’m trying to understand

TCCR1B |= (1 << CS10); //selecting prescaler 0b001 (Tclk/1)

TCCR1B &= ~((1<<CS11) | (1<<CS12)); // turn off CS12 and CS11 bits

TCCR1B |= (1 << CS10), I understood (not sure if correct) that this is changing the current bits on the TCCR1B doing an OR with (1 << CS10), but:

Is it manipulating all bits or only the CS10 bit.

TCCR1B &= ~((1<<CS11) | (1<<CS12)), I understood that this is also manipulating the TCCR1B, but only the bits CS11 and CS12?

So, I appreciate if somebody can explain me … I understood that << to a shift of 2, but I don’t here is the case because if we are manipulating individuals bits, we don’t need to shift

Thanks