| $\frac{2}{9}×\frac{3}{5}$ | $\frac{6}{7}×\frac{7}{9}$ | $\frac{5}{8}×\frac{4}{15}$ | $\frac{9}{20}×\frac{5}{21}$ |
| $\frac{6}{5}×\frac{5}{3}$ | $\frac{7}{25}×\frac{15}{14}$ | $\frac{3}{11}×\frac{1}{2}$ | $\frac{19}{50}×\frac{10}{19}$ |
[主观题]计算。3/7+4/5=5/12+5/8=7/9+6/7=1-2/7-3/7=1/4+1/6+3/4=1/2-1/6=
计算：(1)/(3)×(3)/(5)+1(5)/(7)-(5)/(9)×(5)/(7)1-(5)/(7)×(21)/(25)(1)/(2)+(5)/(4)×(4
[主观题]计算。7/8-5/6=2/9+1/2=6/7-2/3=3/10+1/4=3/7+1/9=1/3-1/5=1/6+1/4=5/7-1/5=
[主观题]4，5，15，6，7，35，8，9，（）A．27B．15C．72D．63
[单选题]4，5，15，6，7，35，8，9，（ ）A．27B．15C．72D．63
[单选题]4，5，15，6，7，35，8，9，（ ）A．27B．15C．72D．63
[单选题]4，5，15，6，7，35，8，9，（ ）。A.27B.15C.72D.63
(1)(2)①②③④⑤⑥⑦⑧⑨⑩(3)(4)(5)①②③④⑤⑥⑦⑧⑨⑩(6)(7)①②③④⑤⑥⑦⑧⑨⑩(8)(9)①②③④⑤(1)(2)①②③④⑤⑥⑦⑧⑨⑩(3
(1)(2)(3)(4)(5)(6)(7)(8)(9)(1)(2)(3)(4)(5)(6)(7)(8)(9)
1.用简便算法计算下面各题。(2)/(9) - (7)/(16) times (2)/(9)(2)/(5) times 4 times (3)/(4)(5)/(