integers are like -4,-3,-2,-1,0,1,2,3,4, etc
ok, so
-21.576
that is a distance of -21.576 from 0
see diagram
-21.5 is like the half way point between the integers -21 and -22
so as you can see, -21.576 is a little bit closer to -22 than -21
so the answer is -22
