Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
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) \(362\times728+326\times272\)
\(=326\times\left(728+272\right)\)
\(=326\times1000\)
\(=326000\)
Bài 2:
a, \(\dfrac{5}{23}\) \(\times\) \(\dfrac{17}{26}\) + \(\dfrac{5}{23}\) \(\times\) \(\dfrac{9}{26}\)
= \(\dfrac{5}{23}\) \(\times\) ( \(\dfrac{17}{26}\) + \(\dfrac{9}{26}\))
= \(\dfrac{5}{23}\) \(\times\) \(\dfrac{26}{26}\)
= \(\dfrac{5}{23}\)
b, \(\dfrac{3}{4}\) \(\times\) \(\dfrac{7}{9}\) + \(\dfrac{7}{4}\) \(\times\) \(\dfrac{3}{9}\)
= \(\dfrac{7}{12}\) + \(\dfrac{7}{12}\)
= \(\dfrac{14}{12}\)
= \(\dfrac{7}{6}\)
`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`
12,3 + 15,629= 27,829
652,24 - 44,85= 607,39
28,5 x 3,56= 101,46
42: 2,4= 17,5
7 giờ 38 phút + 9 giờ 56 phút = 16 giờ 94 phút ( hay 17 giờ 34 phút )
6 giờ 14 phút - 3 giờ 46 phút thành 5 giờ 74 phút-3 giờ 46 phút= 2 giờ 28 phút
23 phút 56 giây x 6 = 138 phút 336 giây ( hay 2 giờ 23 phút 36 giây )
3 ngày 16 giờ : 5 = 17,2 phút
A) x/13+15/26=46/52
x/13+15/26=23/26
x/13=23/26-15/26
x/13=4/13
x=4
a, 23/4 : 3 + 9/4 x 1/3 - 3/8
= 7,8 + 12,22 - 3,8
= 20,02 - 3,8
=16,22
b, 3/5 : 5/6 : 6/7 : 7/8 + 2/5 +23/35
=3/5 x 6/5 x 7/6 x 8/7 + 2/5 + 23/35
=24/25 + 2/5 + 23/35
=1/5 x(24/5 + 2 +23/7)
=1/5 x 353/35
=353/175
a, 46*42+46*5+23*2*10+46*42+46=46*(42+5+10+42+1)=46*100=4600
b,5/3*1/9+5/3*5/9+5/3*7/9-5/3*4/9=5/3*(1/9+5/9+7/9-4/9)=5/3*1=5/3
a) 46 x 42 + 46 x 5 + 23 x 2 x 10 + 46 x 42 + 46
= 46 x 42 + 46 x 5 + 46 x 10 + 46 x 42 + 46
= 46 x (42 + 5 + 10 + 42 + 1)
= 46 x 100
= 4600
b) \(\frac{5}{3}\times\frac{1}{9}+\frac{5}{3}\times\frac{5}{9}+\frac{5}{3}\times\frac{7}{9}-\frac{5}{3}\times\frac{4}{9}\)
\(=\frac{5}{3}\times\left(\frac{1}{9}+\frac{5}{9}+\frac{7}{9}-\frac{4}{9}\right)\)
\(=\frac{5}{3}\times1\)
\(=\frac{5}{3}\)