想想做做 1. 2. 都不对 50+50×7 =50+350=400 40-7×4=40-28=12 15×3-25=45-24=20 3. 2×36+20 190-30×5 78-12×4 =72+20 =190-150 =78-48 =92 =40 =30 4. 92 0 71 15 64 77

想想做做 1. 2. 都不对 50+50×7 =50+350=400 40-7×4=40-28=12 15×3-25=45-24=20 3. 2×36+20 190-30×5 78-12×4 =72+20 =190-150 =78-48 =92 =40 =30 4. 92 0 71 15 64 77