Jeff uses 116 rubber bands to make
a rubber-band ball He estimates
that he has used 448 rubber bands
to make 12 rubber-band balls of the
same size. Use estimation to check
and explain whether his answer
is reasonable or not.

his answer is not reasonable, because if it takes 116 rubber bands to make a rubber band ball, then the most he could make is approximately 3.8 (or 4,) rubber band balls of the same size, if he wanted to make 12 he would need 1392 rubber bands, (116×12=1392,) to make that many.

So NO, his answer is NOT reasonable.