Răspuns :
a) 28-7-7-7-7=0
28-(7x4)=0
28-28=0
b) 40-8-8-8-8-8=0
40(8x5)=0
40-40=0
c) 27-9-9-9=0
27-(7x3)=0
27-27=0
28-(7x4)=0
28-28=0
b) 40-8-8-8-8-8=0
40(8x5)=0
40-40=0
c) 27-9-9-9=0
27-(7x3)=0
27-27=0