8. 5 + 14 + □ = 89 7 + 13 + □ = 46 70 - 3 - □ = 47 80 - 4 - □ = 70

Решение: * 5 + 14 + □ = 89 19 + □ = 89 □ = 89 - 19 □ = 70 * 7 + 13 + □ = 46 20 + □ = 46 □ = 46 - 20 □ = 26 * 70 - 3 - □ = 47 67 - □ = 47 □ = 67 - 47 □ = 20 * 80 - 4 - □ = 70 76 - □ = 70 □ = 76 - 70 □ = 6