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buồn quá . 8 giờ 15 vô học rồi mà ko có ai giải cho mình hết
\(A=\left(\frac{3}{5}+\frac{47}{13}-\frac{25}{8}+\frac{1}{8}-\frac{8}{13}+\frac{2}{5}\right)\times\frac{2014}{2015}\)
\(A=\left[\left(\frac{3}{5}+\frac{2}{5}\right)+\left(\frac{47}{13}-\frac{8}{13}\right)-\left(\frac{25}{8}-\frac{1}{8}\right)\right]\times\frac{2014}{2015}\)
\(A=\left[1+3-3\right]\times\frac{2014}{2015}\)
\(A=1\times\frac{2014}{2015}\)
\(A=\frac{2014}{2015}\)
1) 0,1,2,3,6,10,15,21.
2) 60,30,20,15,12,10.
3) 25,32.37,47,58,71,79,95.
nếu đúng thì kết bạn với mình nha
Bài giải
a, \(81+243+19=\left(81+19\right)+243=100+243=343\)
b, \(2\text{ x }25\text{ x }2\text{ x }16\text{ x }4=25\text{ x }4\text{ x }2\text{ x }2\text{ x }16=25\text{ x }8\text{ x }32=200\text{ x }32=6400\)
c, \(32\text{ x }47+32\text{ x }54-32=32\text{ x }\left(47+54-1\right)=32\text{ x }100=3200\)
a,81+19+243
=100+243
b,(2x25)x2x(16x4)
=50x2x64
=100x64
=6400
c,32x47+32x54-32x1
=32x(47+54-1)
=32x100
=3200
\(\frac{1}{2}\)+ \(\frac{1}{4}\)+ \(\frac{1}{16}\)+ \(\frac{1}{32}\)+ \(\frac{1}{64}\)+ \(\frac{1}{128}\)= \(\frac{123}{234}\)
A = \(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) + \(\dfrac{1}{16}\)+ \(\dfrac{1}{32}\)+\(\dfrac{1}{64}\)+\(\dfrac{1}{128}\)
A\(\times\) 2 = 1 + \(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) + \(\dfrac{1}{16}\)+ \(\dfrac{1}{32}\)+ \(\dfrac{1}{64}\)
A \(\times\) 2 - A = 1 - \(\dfrac{1}{128}\)
A\(\times\)(2-1) = \(\dfrac{128-1}{128}\)
A = \(\dfrac{127}{128}\)
Gọi \(\dfrac{1}{2}+\dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{16}+\dfrac{1}{32}+\dfrac{1}{64}+\dfrac{1}{128}\) là B
\(B=\dfrac{1}{2}+\dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{16}+\dfrac{1}{32}+\dfrac{1}{64}+\dfrac{1}{128}\)
\(2\cdot B=1+\dfrac{1}{2}+\dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{12}+\dfrac{1}{32}+\dfrac{1}{64}\)
\(2\cdot B-B=1+\dfrac{1}{2}+\dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{12}+\dfrac{1}{32}+\dfrac{1}{64}-\left(\dfrac{1}{2}+\dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{16}+\dfrac{1}{32}+\dfrac{1}{64}+\dfrac{1}{128}\right)\)
\(B=1+\left(\dfrac{1}{2}-\dfrac{1}{2}+\dfrac{1}{4}-\dfrac{1}{4}+.....+\dfrac{1}{64}-\dfrac{1}{64}\right)-\dfrac{1}{128}\)
\(B=1+0-\dfrac{1}{128}\)
\(B=1-\dfrac{1}{128}\)
\(B=\dfrac{128}{128}-\dfrac{1}{128}\)
\(B=\dfrac{127}{128}\)
a, 53 x 39 + 47 x 39 + 53 x 21- 47 x 21
= ( 53 + 47 ) x 39 + ( 53 - 47 ) x 21
= 100 x 39 + 6 x 21
= 3900 + 126
= 4026
Mấy phần khác bạn tự làm đi
nhiều thế!
1.a /4 giờ 18 phút + 15 giờ 45 phút =20 giờ 3 phút
b/12 giờ 34 giây - 5 phút 47 giây = 6 giờ 47 phút
c/12 giờ 34 phút x 3 =1 ngày 13 giờ 42 phút
d/ 10 phút 48 giây : 9 = 1 giờ 12 phút
`2.a / 14/15 + 3/11 + 1/15 +3/11 +10/22 =3/11+(14/15 + 1/15) + 10/22
= 3/11+ 1 + 10/22
= 4/11 + 10 /22
= 18/22
b/9,25 + 9,25 x 8 + 9,25 = 9,25 x (8 + 2)
= 9,25 x 10
= 92,5
Xong rồi nhé.
\(\frac{12}{15}\times\frac{22}{47}+\frac{25}{47}:\frac{15}{12}\)
\(\frac{12}{15}\times\frac{22}{47}+\frac{25}{47}\times\frac{12}{15}\)
\(=\frac{12}{15}\times\left(\frac{22}{47}+\frac{25}{47}\right)\)
\(=\frac{12}{15}\times\frac{22+25}{47}\)
\(=\frac{12}{15}\times1=\frac{12}{15}\)