Giải bài 5 trang 118 - SGK Toán 4

Tính:

b) $\dfrac{4\,\times\,5\,\times\,6}{12\,\times\,15\,\times\,9}=\dfrac {\cancel{4} \times \cancel{5} \times {6}} {\cancel{12} \times \cancel{15} \times {9}}=\dfrac{1\,\times\,1\,\times\,6}{3\,\times\,3\,\times\,9}=\dfrac {{1} \times {1} \times \cancel{6}} {\cancel{3} \times {3} \times {9}}=\dfrac{2}{27}$

c) $\dfrac{6\,\times\,8\,\times\,11}{33\,\times\,16} = ​​\dfrac{2\times3\,\times\,8\,\times\,11}{11\times3\,\times\,16}=\dfrac {{2} \times \cancel{3}\times \cancel{8} \times\cancel {11}} {\cancel{11} \times \cancel{3} \times \cancel{16}}=\dfrac{2}{2}=1$