Răspuns :
16 = ( 1+ 1+ 1+ 1+ 1+ 1+ 2) *2 = 4*1 + 4*1 + 4*1 + 4*1
20 = ( 1+ 1+ 1+ 1+ 1+ 1+ 1+ 1+ 2) *2 = 4*1+ 4*1+ 4*1+ 4*1+ 4*1
20 = ( 1+ 1+ 1+ 1+ 1+ 1+ 1+ 1+ 2) *2 = 4*1+ 4*1+ 4*1+ 4*1+ 4*1