1:(2 + 4 ÷ 10) × 102:(2 + (4 ÷ 10)) × 103:(4 ÷ 10 + 2) × 104:((4 ÷ 10) + 2) × 105:10 × (2 + 4 ÷ 10)6:10 × (2 + (4 ÷ 10))7:10 × (4 ÷ 10 + 2)8:10 × ((4 ÷ 10) + 2)给我点分吧