903______899 | 432______389 | 301______495 | 999______1000 | 709______790 | 98______101 | 670-600______70 | 50+500______500-50 | 890______980 | 2970______2097 | 8000克______8千克 | 5500克______5千克 | 2002______2020 | 38-25______42-25 | 3千克______3000克 | 48+36______46+38 | 90÷5______48÷2 | 300克+100克______1千克. |
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