If I asked: Would you sacrifice your life to save 5 random people, most people would say no.
So most people think that 1 life > 5 lives.
I guess they failed at moral math.
They will say things like "My life is precious to me". So in their eyes, one life is more precious than five lives. Then when I ask "Why is your one life more precious than five other lives?" I get no answer, as expected. There is no answer to it. You cannot explain why you are more important than 5 other people, because you are not more important than 5 other people.
Thats why the abortionists cant explain why
1 woman is more important than 1000 children.
Or why 1>1000.
Its hard to explain indeed, because to do that you have to pretend to care about life and at the same time be supportive of an action that destroyed over 1 billion lives.
So yes, logically, you have moral obligation to save lives.