Bài 1 trang 162 (Phép nhân) SGK Toán 5

Tính:

a) \(4802 × 324 ;\)                   \(6120 × 205 ;\)

b) \(\dfrac{4}{17} × 2 ;\)                         \(\dfrac{4}{7} × \dfrac{5}{12}\) ;

c) \(35,4 × 6,8 ;\)                    \(21,76 × 2,05 .\)

Lời giải

b) \(\dfrac{4}{17}\times  2  = \dfrac{8}{17}\);

    \(\dfrac{4}{7} \times \dfrac{5}{12} = \dfrac{4 \times 5}{7 \times 12}= \dfrac{20}{84} = \dfrac{5}{21}\) ;


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