Giải bài 1 trang 30 - SGK Toán lớp 5

Hướng dẫn:

$1ha = 10 \, 000m^2 \\ 1km^2 = 1 \, 000 \, 000m^2 \\ 1dm^2 = \dfrac{1}{100}m^2 \\ 1cm^2 = \dfrac{1}{10\, 000}m^2$

Bài giải:

$\begin{align} & a)\,5ha=50\,000{{m}^{2}} \\ & 2k{{m}^{2}}=2\,000\,000{{m}^{2}} \\ \\ & b)\,400\text{d}{{m}^{2}}=4{{m}^{2}} \\ & 1500\text{d}{{m}^{2}}=15{{m}^{2}} \\ & 70\,000c{{m}^{2}}=7{{m}^{2}} \\ \\ & c)\,\,26{{m}^{2}}17\text{d}{{m}^{2}}=26\frac{17}{100}{{m}^{2}} \\ & 90{{m}^{2}}5\text{d}{{m}^{2}}=90\frac{5}{100}{{m}^{2}} \\ & 35\text{d}{{\text{m}}^{2}}=\frac{35}{100}{{m}^{2}} \\ \end{align}$