Tính Bằng cách thuận tiện
A) 4/5 x 1/4 + 1/2 x 4/5
B) 3/4 x 4/5 + 5/6 x 6/7 x 7/8
Giải nhanh ạ mk đg cần gấp
Tính bằng cách thuận tiện
a. 5/7 x 5/9 + 4/9 x 5/7
b. 1/10 + 5/9 + 4/9 + 9/10 – 1
c. 5/7 x 5/9 + 4/9 x 5/7 + 2/7
d. 2/7 + 2/8 + 1/4 + 1/7 + 4/7
e. 4/5 + 3/10 + 2/10 + 0,7
f. 326 x 728 + 326 x 272
a) \(\dfrac{5}{7}\times\dfrac{5}{9}+\dfrac{4}{9}\times\dfrac{5}{7}\)
\(=\dfrac{5}{7}\times\left(\dfrac{4}{9}+\dfrac{5}{9}\right)\)
\(=\dfrac{5}{7}\times1\)
\(=\dfrac{5}{7}\)
b) \(\dfrac{1}{10}+\dfrac{5}{9}+\dfrac{4}{9}+\dfrac{9}{10}-1\)
\(=\left(\dfrac{5}{9}+\dfrac{4}{9}\right)+\left(\dfrac{1}{10}+\dfrac{9}{10}-1\right)\)
\(=1+0\)
\(=1\)
c) \(\dfrac{5}{7}\times\dfrac{5}{9}+\dfrac{4}{9}\times\dfrac{5}{7}+\dfrac{2}{7}\)
\(=\dfrac{5}{7}\times\left(\dfrac{5}{9}+\dfrac{4}{9}\right)+\dfrac{2}{7}\)
\(=\dfrac{5}{7}+\dfrac{2}{7}\)
\(=1\)
d) \(\dfrac{2}{7}+\dfrac{2}{8}+\dfrac{1}{4}+\dfrac{1}{7}+\dfrac{4}{7}\)
\(=\left(\dfrac{2}{8}+\dfrac{1}{4}\right)+\left(\dfrac{2}{7}+\dfrac{1}{7}+\dfrac{4}{7}\right)\)
\(=\left(\dfrac{1}{4}+\dfrac{1}{4}\right)+1\)
\(=\dfrac{1}{2}+1\)
\(=\dfrac{3}{2}\)
e) \(\dfrac{4}{5}+\dfrac{3}{10}+\dfrac{2}{10}+0,7\)
\(=\dfrac{4}{5}+\dfrac{5}{10}+\dfrac{7}{10}\)
\(=\dfrac{4}{5}+\dfrac{12}{10}\)
\(=\dfrac{4}{5}+\dfrac{6}{5}\)
\(=\dfrac{10}{5}\)
\(=2\)
g) \(362\times728+326\times272\)
\(=326\times\left(728+272\right)\)
\(=326\times1000\)
\(=326000\)
tính bằng cách thuận tiện
a .1/10 + 2/10 + 3/10 + 4/10 + 5/10 + 6/10 + 7/10 + 8/10 + 9/10
b. 13,25 : 0,5 + 13,25 : 0,25 + 13,25 : 0,125 + 13,25 x 6
`a)1/10 + 2/10 + 3/10 + 4/10 + 5/10 + 6/10 + 7/10 + 8/10 + 9/10`
`=(1/10+9/10)+(2/10+8/10)+(3/10+7/10)+(4/10+6/10)+5/10`
`=10/10 + 10/10+10/10+10/10+1/2`
`=1+1+1+1+1/2`
`=2+2+1/2`
`=4+1/2`
`=8/2+1/2`
`=9/2`
__
`13,25:0,5+13,25:0,25+13,25:0,125+13,25×6`
`=13,25×1/(0,5)+13,25×1/(0,25)+13,25×1/(0,125)+13,25×6`
`=13,25×(1/(0,5)+1/(0,25)+1/(0,125)+6)`
`=13,25×(2+4+8+6)`
`=13,25×20`
`=265`
`#QiN`
Bài 1. Tính bằng cách thuận tiện nhất:
a)(1/3+1/5)x1/4 b)5/3 x 4/5 x 6/7 c) 2/5 x 3/7 + 2/5 x 4/7
a: =8/15x1/4=2/15
b: \(=\dfrac{5}{3}\cdot\dfrac{4}{5}\cdot\dfrac{6}{7}=\dfrac{24}{21}=\dfrac{8}{7}\)
c: \(=\dfrac{2}{5}\left(\dfrac{3}{7}+\dfrac{4}{7}\right)=\dfrac{2}{5}\)
Tính bằng cách thuận tiện nhất: a. 60 x (7/12 + 4/15) b. 1/2 x 2/3 x 3/4 x 4/5 x 5/6 x 6/7 x 7/8 x 8/9 Mik sẽ tk cho ai nhanh và đúng nhất 😁😁
1.Tính bằng cách thuận tiện nhất :
(6/7 - 2/7) : 4/9 x 3 =
7/11 x 5/6 + 4/11 x 5/6 =
1,
a,=4/7:4/9.3
=9/7.3
=27/7
b,=(7/11+4/11).5/6
=1.5/6
=5/6
`(6/7-2/7):4/9xx3=4/7xx9/4xx3=[4xx9xx3]/[7xx4]=27/7`
`7/11xx5/6+4/11xx5/6=(7/11+4/11)xx5/6=11/11xx5/6=5/6`
tính bằng cách thuận tiện nhất :
1/2 x 2/3 x 3/4 x 4/5 x 5/6
1/10 x 2/9 x 3/8 x 4/7 x 5/6 x 6/5 x 7/4 x 3/8 x 9/2
2 năm sau mày sẽ chết do dịch bệnh
Tính nhanh:
a, 5/6 x 4/5 + 4/5 x 1/6 + 4/5
b, 60 x (7/12 + 4/15)
Xin lời giải chi tiết ạ
\(a,\dfrac{5}{6}\times\dfrac{4}{5}+\dfrac{4}{5}\times\dfrac{1}{6}+\dfrac{4}{5}=\dfrac{4}{5}\times\left(\dfrac{5}{6}+\dfrac{1}{6}+1\right)=\dfrac{4}{5}\times2=\dfrac{8}{5}\)
\(b,60\times\left(\dfrac{105}{180}+\dfrac{48}{180}\right)=60\times\dfrac{17}{20}=51\)
a) \(\dfrac{5}{6}\times\dfrac{4}{5}+\dfrac{4}{5}\times\dfrac{1}{6}+\dfrac{4}{5}\)
\(=\dfrac{5}{6}\times\dfrac{4}{5}+\dfrac{4}{5}\times\dfrac{1}{6}+\dfrac{4}{5}\times1\)
\(=\dfrac{4}{5}\times\left(\dfrac{5}{6}+\dfrac{1}{6}+1\right)\)
\(=\dfrac{4}{5}\times2\)
\(=\dfrac{8}{5}\)
b) \(60\times\left(\dfrac{7}{12}+\dfrac{4}{15}\right)\)
\(=60\times\dfrac{17}{20}\)
\(=\dfrac{1020}{20}\)
\(=51\)
tính bằng cách thuận tiện nhất 1/2 x 2/3 x 3/4 x 4/5 x 5/6 x 6/7 x 7/8 x 8/9
Tao mách cô mày hỏi bài thi nhá
`1/2 xx 2/3 xx 3/4 xx 4/5 xx 5/6 xx 6/7 xx 7/8 x 8/9`
`= [1 xx 2 xx 3 xx 4 xx 5 xx 6 xx 7 xx 8]/[2 xx 3 xx 4 xx 5 xx 6 xx 7 xx 8 xx 9]`
`= 1/9`
HT~