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` 1/2 + 3/4 - 5/6 = 6/12 + 9/12 - 10/12 = 5/12`
` ( 5/6 + 3/8) xx 2/7 = ( 15/24 + 9/24) xx 2/7 = 29/24 xx 2/7 = 29/84`
` ( 7/6 - 3/4) : 3/5 = ( 14/12 - 9/12) : 3/5 = 5/12 : 3/5 = 5/12 xx 5/3 = 25/36`
` 6/7 xx 2/3 : 5/7 = 6/7 xx 2/3 xx 7/5 = 4/5`
Bài 5:
a: =1/3+2/5
=5/15+6/15
=11/15
b: =6/21+12/21=18/21=6/7
c: =16/24+10/24
=26/24
=13/12
d: =4/12+3/12+10/12
=17/12
e: =19/24-9/24
=10/24
=5/12
f: =8/9-3/9=5/9
g: =9/3+1/3=10/3
k: =15/24+42/24+14/24
=71/24
a) = 1/2 - 1/2 + 1/3 -1/3 + 1/4 - 1/4 + 1/5 - 1/5 + 1/6
= 0 + 0 + 0 + 0 + 1/6
= 1/6
b) 2/3 + 2/4 - 2/4 + 2/5 - 2/5 + 2/6 - 2/6 + 2/7 - 2/7 + 28
= 2/3 + 28
= 86/3
[tick cho mik nha]
Tính:
2/7 + 5/7=1
8/15 + 6/15 =14/15
2/9 + 3/9 + 4/9=9/9=1
[ Không cần làm phép tính ]Điền vào ô trống <,>,= :
3/5 + 1/5 = 1/5 + 3/5
7/9 + 1/9 < 7/9 + 1/9 + 1/9
3/7 + 2/7 < 3/7 + 4/7
1/5 + 3/5 < 2/5 + 3/5
Tính:
2/7 + 5/7=1
8/15 + 6/15 =14/15
2/9 + 3/9 + 4/9=9/9=1
[ Không cần làm phép tính ]Điền vào ô trống <,>,= :
3/5 + 1/5 = 1/5 + 3/5
7/9 + 1/9 < 7/9 + 1/9 + 1/9
3/7 + 2/7 < 3/7 + 4/7
1/5 + 3/5 < 2/5 + 3/5
cách 1 \(\left(\dfrac{6}{11}+\dfrac{7}{5}\right)\cdot\dfrac{3}{7}\\ =\dfrac{107}{55}\cdot\dfrac{3}{7}=\dfrac{321}{385}\)cách 2 \(\left(\dfrac{6}{11}+\dfrac{7}{5}\right)\cdot\dfrac{3}{7}\\ =\dfrac{6}{11}\cdot\dfrac{3}{7}+\dfrac{7}{5}\cdot\dfrac{3}{7}\\ =\dfrac{18}{77}+\dfrac{3}{5}=\dfrac{321}{385}\)
cách 1 \(\left(\dfrac{6}{7}-\dfrac{1}{2}\right)\cdot\dfrac{2}{5}\\ =\dfrac{5}{14}\cdot\dfrac{2}{5}=\dfrac{1}{7}\) cách 2 \(\left(\dfrac{6}{7}-\dfrac{1}{2}\right)\cdot\dfrac{2}{5}\\ =\dfrac{6}{7}\cdot\dfrac{2}{5}-\dfrac{1}{2}\cdot\dfrac{2}{5}\\ =\dfrac{12}{35}-\dfrac{1}{5}=\dfrac{1}{7}\)
[ \(\dfrac{6}{11}\) + \(\dfrac{7}{5}\)] x \(\dfrac{3}{7}\)
= [ \(\dfrac{30}{55}\) + \(\dfrac{77}{55}\)] x \(\dfrac{3}{7}\)
= \(\dfrac{107}{55}\)x \(\dfrac{3}{7}\)
= \(\dfrac{321}{385}\)
[ \(\dfrac{6}{11}\) + \(\dfrac{7}{5}\)] x \(\dfrac{3}{7}\)
= \(\dfrac{6}{11}\) x \(\dfrac{3}{7}\) + \(\dfrac{7}{5}\) x \(\dfrac{3}{7}\)
= \(\dfrac{18}{77}\) + \(\dfrac{3}{5}\)
= \(\dfrac{90}{385}\) + \(\dfrac{231}{385}\)
= \(\dfrac{321}{385}\)
[ \(\dfrac{6}{7}\) - \(\dfrac{1}{2}\)] x \(\dfrac{2}{5}\)
= [ \(\dfrac{12}{14}\) - \(\dfrac{7}{14}\)] x \(\dfrac{2}{5}\)
= \(\dfrac{5}{14}\) x \(\dfrac{2}{5}\)
= \(\dfrac{1}{7}\)
[ \(\dfrac{6}{7}\) - \(\dfrac{1}{2}\)] x \(\dfrac{2}{5}\)
= \(\dfrac{6}{7}\) x \(\dfrac{2}{5}\) - \(\dfrac{1}{2}\) x \(\dfrac{2}{5}\)
= \(\dfrac{12}{35}\) - \(\dfrac{1}{5}\)
= \(\dfrac{12}{35}\) - \(\dfrac{7}{35}\)
= \(\dfrac{5}{35}\)
= \(\dfrac{1}{7}\)
bn có tíc ko zậy ?
Châu Á là châu lục lớn nhất về diện tích và dân số 4.623.940.078 người (cập nhật 30/01/2020 theo số liệu từ Liên Hợp Quốc), có diện tích khoảng 49.7 triệu km2 chiếm hơn 30% phần đất liền trên trái đất.
1. a) \(\frac{6}{11}+\frac{7}{5}=\frac{30}{55}+\frac{77}{55}=\frac{30+77}{55}=\frac{107}{55}\)
b) \(\frac{9}{5}-\frac{6}{7}=\frac{63}{35}-\frac{30}{35}=\frac{63-30}{35}=\frac{33}{35}\)
c) \(\frac{11}{2}-3=\frac{11}{2}-\frac{3}{1}=\frac{11}{2}-\frac{6}{2}=\frac{11-6}{2}=\frac{5}{2}\)
d) \(15+\frac{1}{3}=\frac{15}{1}+\frac{1}{3}=\frac{45}{3}+\frac{1}{3}=\frac{45+1}{3}=\frac{46}{3}\)
2. a)\(\frac{3}{7}\cdot\frac{7}{2}=\frac{21}{14}\)
b) \(6\cdot\frac{7}{9}=\frac{42}{9}\)
c) \(\frac{8}{15}\cdot5=\frac{40}{15}\)
d) \(\frac{6}{13}\cdot\frac{26}{2}=\frac{156}{26}\)
Dấu chấm mấy bài trên thay thế cho dấu nhân nhá..
`1/3 + 1/5 -1/4`
`= 5/15 + 3/15 -1/4`
`= 8/15 -1/4`
`= 17/60`
__
`7/8 -(1/4 + 2/5)`
`= 7/8-1/4 - 2/5`
`= 7/8 - 2/8 -2/5`
`= 5/8 -2/5`
`= 9/40`
__
`5/11-(3/5 -6/11)`
`= 5/11 -3/5 +6/11`
`= (5/11 + 6/11)-3/5`
`= 1 -3/5`
`= 5/5-3/5`
`=2/5`
__
`5/7 - ( 19/35 - 6/15)`
`= 5/7 - 19/35 + 6/15`
`= 25/35 -19/35 + 6/15`
`=6/35 +6/15`
`=4/7`
Hướng dẫn giải: