Câu hỏi của vũ tô bình phương

Bài 5:\(72\cdot61+72\cdot42-216\)\(=72\left(61+42\right)-72\cdot3\)\(=72\left(103-3\right)\)\(=72\cdot100=7200\)Bài 4:\(2,2ha=22000m^2\)\(0,63ha=6300m^2\)\(5863m^2=0,5863ha\)\(128m^2=0,0128ha\)\(3m^28dm^2=3,08m^2\)\(12m^235cm^2=12,0035m^2\)\(7km^215ha=7,15km^2\)\(6m^2128cm^2=6,0128m^2\)Câu trả lời: Bài 5:\(72\cdot61+72\cdot42-216\)\(=72\left(61+42\right)-72\cdot3\)\(=72\left(103-3\right)\)\(=72\cdot100=7200\)Bài 4:\(2,2ha=22000m^2\)\(0,63ha=6300m^2\)\(5863m^2=0,5863ha\)\(128m^2=0,0128ha\)\(3m^28dm^2=3,08m^2\)\(12m^235cm^2=12,0035m^2\)\(7km^215ha=7,15km^2\)\(6m^2128cm^2=6,0128m^2\)