Tính:
a) 683 \(\times\) 35; 1954 \(\times\) 425; 2438 \(\times\) 306.
b) \(\dfrac{7}{9}\times\dfrac{3}{35}\); \(\dfrac{9}{22}\times\) 55; \(\dfrac{11}{17}:\dfrac{33}{34}\).
c) 36,66 \(:\) 7,8; 15,7 \(:\) 6,28; 27,63 \(:\) 0,45.
d) 16 giờ 15 phút \(:\) 5; 14 phút 36 giây \(:\) 12.
a) 683\(\times\) 35=23906
1954\(\times\) 425=830450
2438\(\times\) 306=746028
b) \(\dfrac{7}{9}\times\dfrac{3}{35}=\dfrac{7\times3}{9\times35}=\dfrac{1}{15}\)
\(\dfrac{9}{22}\times55=\dfrac{9\times55}{22}=\dfrac{45}{2}\)
\(\dfrac{11}{17}:\dfrac{33}{34}=\dfrac{11}{17}\times\dfrac{34}{33}=\dfrac{11\times34}{17\times33}=\dfrac{2}{3}\)
c) 36,66:7,8=4,7
15,7:6,28=2,5
27,63:0,45=61,4
d) 16 giờ 15 phút:5=3 giờ 15 phút
14 phút 36 giây:12=1 phút 13 giây