Răspuns:
(2 + 3) x 5 =5×5=25
(2+3)×5=2×5+3×5=10+15=25
(4+5) x 8 =9×8=72
(4+5)×8=4×8+5×8=32+40=72
(9-4) x 8 = 5×8=40
(9-4)×8=9×8-4×8=72-32=40
(2 + 1 + 3) x 4 = 6×4=24
(2+1+3)×4=2×4+1×4+3×4=8+4+12=24
(8-3) x 7 = 5×7=35
(8-3)×7=8×7-3×7=56-21=35
(5+1+2) x 7 =8×7=56
(5+1+2)×7=5×7+1×7+2×7=35+7+14=56