`(5/8 m^{2} + 3/8 m^{2}) xx 2`
`= (5/8 + 3/8) m^{2} xx 2`
`= 1 m^{2} xx 2`
`= 2 m^{2}`
$\Rightarrow$ $\text{Điền 2}$
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`7/5 ha - 1/2 ha `
`= (7/5 - 1/2) ha`
`= (14/10 - 5/10) ha`
`= 9/10 ha`
`= 9 dam^{2}`
$\Rightarrow$ $\text{Điền 9}$
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`2/7 m^{2} : 2 + 6 m^{2}`
`= 2/7 m^{2} . 1/2 + 6 m^{2} `
`= 1/7 m^{2} + 6 m^{2} `
`= 43/7 m^{2} `
$\Rightarrow$ $\text{Điền}$ ` 43/7 `