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![](https://rs.olm.vn/images/avt/0.png?1311)
a, 2/8 + 5/6 = 1/4 +5/6 = 6/24 + 20/24 = 26/24
b,1/8 + 12/16 = 1/8 + 3/4 = 4/32 + 24/32 = 28/32
c, 1/4 + 6/30 = 1/4 + 1/5 = 5/20 + 4/20 = 9/29
d, 12/18 + 12/42 = 2/3 + 2/7 = 14/21 + 6/21 = 20/21
nhé
Bài 6 : rút gọn rồi tính
A ) 2/8 + 5/6 = 3/12 + 10/12 = 13/12.
B ) 1/8 + 12/16 = 1/8 + 6/8 = 7/8.
C ) 1/4 + 6/30 = 5/20+ 4/20 = 9/20.
D ) 12/18 + 12/42 = 14/21 + 6/21 = 20/21.
![](https://rs.olm.vn/images/avt/0.png?1311)
a: =8/5-2/3=24/15-10/15=14/15
12/20-6/18=3/5-1/3=9/15-5/15=4/15
b: 18/21-12/27=6/7-7/9=54/63-49/63=5/63
8/12-20/50=2/3-2/5=10/15-6/15=4/15
\(a,\dfrac{8}{5}-\dfrac{18}{27}=\dfrac{8}{5}-\dfrac{2}{3}=\dfrac{14}{15}\\ \dfrac{12}{20}-\dfrac{6}{18}=\dfrac{3}{5}-\dfrac{1}{3}=\dfrac{4}{15}\\ b,\dfrac{18}{21}-\dfrac{12}{27}=\dfrac{6}{7}-\dfrac{4}{9}=\dfrac{26}{63}\\ \dfrac{8}{12}-\dfrac{20}{50}=\dfrac{2}{3}-\dfrac{2}{5}=\dfrac{4}{15}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
12/18 + 12/42 = 2/3 + 2/7 = 14/21 + 6/21 = 20/21
1/2 + 2/4 + 3/6 + 4/8 + 5/10 + 6/12
= 1/2 + 1/2 + 1/2 + 1/2 + 1/2 + 1/2
= 1/2 x 6
=6/2
=3
![](https://rs.olm.vn/images/avt/0.png?1311)
1.
a, Ta có 28=14⇒14+56=1312(Bn tự quy đồng lên nhé !)
b,Ta có1216=34⇒18+34=78(Bn tự quy đồng lên nhé !)
c,Ta có636=16⇒14+16=512(Bn tự quy đồng lên nhé !)
d,Ta có1218=23⇒23+14=1112(Bn tự quy đồng lên nhé !)
7.Phần này mk chỉ cho đáp án thuia.67 ;
b,420=15 ;
c,615 ;
d,129
![](https://rs.olm.vn/images/avt/0.png?1311)
Nay rảnh lại qua làm mấy bài lớp 4 ^^
Tui làm luôn kh ghi đề nhá
1,
\(\frac{2}{3}+\frac{8}{15}=\frac{6}{5}\)
\(\frac{2}{5}+\frac{2}{3}=\frac{16}{15}\)
\(\frac{2}{3}+\frac{5}{6}=\frac{3}{2}\)
2,
\(\cdot\frac{3}{7}+\frac{6}{5}+\frac{4}{7}\)
\(=\frac{3}{7}+\frac{4}{7}+\frac{6}{5}\)
\(=1+\frac{6}{5}\)
\(=\frac{11}{5}\)
\(\cdot\frac{6}{4}+\frac{7}{3}+\frac{4}{4}+\frac{3}{3}\)
\(=\frac{6}{4}+\frac{4}{4}+\frac{7}{3}+\frac{3}{3}\)
\(=\frac{10}{4}+\frac{10}{3}\)
\(=\frac{35}{6}\)
23+815=6523+815=65
25+23=161525+23=1615
23+56=3223+56=32
2,
⋅37+65+47⋅37+65+47
=37+47+65=37+47+65
=1+65=1+65
=115=115
⋅64+73+44+33⋅64+73+44+33
=64+44+73+33=64+44+73+33
=104+103=104+103
=356
![](https://rs.olm.vn/images/avt/0.png?1311)
b: 12/20+6/18=3/5+1/3=9/15+5/15=14/15
c: 8/12+20/30=2/3+2/3=4/3
d: 10/12+12/36=5/6+2/6=7/6
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(\dfrac{5}{6}-\dfrac{2}{14}\)
\(=\dfrac{5}{6}-\dfrac{1}{7}\)
\(=\dfrac{35}{42}-\dfrac{6}{42}\)
\(=\dfrac{29}{42}\)
b) \(\dfrac{5}{20}-\dfrac{1}{6}\)
\(=\dfrac{1}{4}-\dfrac{1}{6}\)
\(=\dfrac{3}{12}-\dfrac{2}{12}\)
\(=\dfrac{1}{12}\)
c) \(\dfrac{5}{9}-\dfrac{3}{12}\)
\(=\dfrac{5}{9}-\dfrac{1}{4}\)
\(=\dfrac{20}{36}-\dfrac{9}{36}\)
\(=\dfrac{11}{36}\)
d) \(8-\dfrac{4}{6}\)
\(=\dfrac{48}{6}-\dfrac{4}{6}\)
\(=\dfrac{44}{6}=\dfrac{22}{3}\).
2/8 + 5/6 = 13/12
1/8 + 12/16 = 7/8
1/4 + 6/30 = 1/2
12/18 + 12/42 = 60/63
A ) 2/8 + 5/6 = 12/48 + 40/48 = 52/48
B) 1/8 + 12/16 = 16/128 + 96/128
C) 1/4 + 6/30 = 30/120 + 24/120 = 54/120
D) 12/18 + 12/42 = 504/756 + 216/756 = 720/756
Sai thì thoi