Рішити по діях 39-(25-7+5)+4= 21+(67-9)-(6+8)=
39 - (25 - 7 + 5) + 4 = 20 21 + (67 - 9) - (6 + 8) = 65 1) 25 - 7 = 18 1) 67 - 9 = 58 2) 18 + 5 = 23 2) 6 + 8 = 14 3) 39 - 23 = 16 3) 21 + 58 = 79 4) 16 + 4 = 20 4) 79 - 14 = 65