求未知数x
| x÷12=36 | 25×x=400 |
| 31+47=________ | 720÷6=________ | 900×5=________ | 46-18=________ |
| 380+530=________ | 680÷4=________ | 16×6=________ | 710-420=________ |
| 810-490=________ | 80÷5=________ | 120×7=________ | 340+270=________ |
| 700-50×6=________ | 420÷2×3=________ | (74+26)×4=________ | 100×2+3=________ |
| 700-400+200=________ | 180÷(3×3)=________. |