3头牛、8只羊一天共吃草86千克，5头牛、15只羊一天共吃草150千克，求一头牛和一只羊一天共吃草多少千克？
口算
55+37= 80﹣26= 1400﹣800= 2+210= 9+300=
82+0= 1﹣
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口算我最棒.
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= 1+
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﹣0.2=
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0.32=
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= 2x+x=
240﹣40÷4= 125×（8+8）= ÷12=6 2000×3+60=
320×11÷32= 1﹣
= 24×5﹣25×4= 8×13×25=
4005÷19≈
口算．
300×7= 40+300= 58÷7= 40×8=
720﹣90= 3200﹣3000= 0×800= 45÷9=
5×60= 4+6×4= 604×3≈ 695×9≈
705+196≈ 397×4≈ 78×5≈
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1﹣
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= 80﹣20×0=