a, 4/5-1/2+1/3 b, 2/7:2/3-1/7 c, 2/9:2/9×1/2 d, 2/5+1/2+7/10 e, 9/20-8/15×5/12 g, 4/9+11/8-5/6 h, 2/3:4/5:7/12 Giải giúp mình với ạ mình cảm ơn
a, 4/5-1/2+1/3 b, 2/7:2/3-1/7 c, 2/9:2/9×1/2 d, 2/5+1/2+7/10 e, 9/20-8/15×5/12 g, 4/9+11/8-5/6 h, 2/3:4/5:7/12 Giải giúp mình với ạ mình cảm ơn
Đáp án:
a, $\dfrac{4}{5}$ – $\dfrac{1}{2}$ + $\dfrac{1}{3}$
=$\dfrac{24}{30}$ – $\dfrac{15}{30}$ + $\dfrac{10}{30}$
= $\dfrac{9}{30}$ + $\dfrac{10}{30}$
= $\dfrac{19}{30}$
b, $\dfrac{2}{7}$ : $\dfrac{2}{3}$ – $\dfrac{1}{7}$
= $\dfrac{2}{7}$ x $\dfrac{3}{2}$ -$\dfrac{1}{7}$
= $\dfrac{6}{14}$ -$\dfrac{1}{7}$
= $\dfrac{6}{14}$ – $\dfrac{2}{14}$
= $\dfrac{4}{14}$
= $\dfrac{2}{7}$
c, $\dfrac{2}{9}$ : $\dfrac{2}{9}$ x $\dfrac{1}{2}$
= 1 x $\dfrac{1}{2}$
= $\dfrac{1}{2}$
d $\dfrac{2}{5}$ + $\dfrac{1}{2}$ + $\dfrac{7}{10}$
= $\dfrac{4}{10}$ + $\dfrac{5}{10}$ + $\dfrac{7}{10}$
= $\dfrac{16}{10}$
= $\dfrac{8}{5}$
e, $\dfrac{9}{20}$ – $\dfrac{8}{15}$ x $\dfrac{5}{12}$
= $\dfrac{9}{20}$ – $\dfrac{40}{180}$
= $\dfrac{81}{180}$ – $\dfrac{40}{180}$
=$\dfrac{41}{180}$
g , $\dfrac{4}{9}$ + $\dfrac{11}{8}$ – $\dfrac{5}{6}$
= $\dfrac{32}{72}$ + $\dfrac{99}{72}$ – $\dfrac{60}{72}$
= $\dfrac{131}{72}$ – $\dfrac{60}{72}$
= $\dfrac{71}{72}$
h ,$\dfrac{2}{3}$ : $\dfrac{4}{5}$ : $\dfrac{7}{12}$
= $\dfrac{2}{3}$ x $\dfrac{5}{4}$ x $\dfrac{12}{7}$
=$\dfrac{120}{84}$
= $\dfrac{10}{7}$
a, 4/5 -1/2 +1/3= 3/10+ 1/3
=19/30
b, 2/7:2/3 -1/7 =2/7: 11/21
=6/11
c, 2/9:2/9×1/2 =1x 1/2
=1/2
d, 2/5+1/2+7/10 =9/10 +7/10
= 8/5
e, 9/20- 8/15x 5/12 = 9/20- 2/9
=41/180
g, 4/9+11/8 -5/6= 131/72 -5/6
=71/72
h, 2/3:4/5 :7/12 = 5/6:7/12
=10/7