1:(2 × 5 - 7) × 8=242:((2 × 5) - 7) × 8=243:(5 × 2 - 7) × 8=244:((5 × 2) - 7) × 8=245:8 × (2 × 5 - 7)=246:8 × ((2 × 5) - 7)=247:8 × (5 × 2 - 7)=248:8 × ((5 × 2) - 7)=24