\(\frac{1}{4}\cdot45+0.25\cdot35+\frac{25}{100}\cdot19+25\%\)

\(=0.25\cdot45+0.25\cdot35+0.25\cdot19+0.25\)

\(=0.25\left(45+35+19+1\right)\)

\(=0.25\cdot100\)

\(=25\)

\(=0,25.45+0,25.35+0,25.19+0,25.1\)

\(=0,25.\left(45+35+19+1\right)\)

\(=0,25.100\)

\(=25\)

\(\frac{1}{4}\times45+0,25\times35+\frac{25}{100}\times19+25\%\)

\(=0,25\times45+0,25\times35+0,25\times19+0,25\)

\(=0,25\times\left(45+35+19+1\right)\)

\(=0,25\times100=25\)

4 giờ 45 phút + 6 giờ 28 phút = 10 giờ 73 phút = 11 giờ 13 phút

15 giờ 16 phút - 7 giờ 30 phút = 14 giờ 76 phút - 7 giờ 30 phút = 7 giờ 46 phút

b) \(\dfrac{1}{4}\cdot28+25\%\cdot32+\dfrac{25}{100}\cdot39+0,25\)

\(=0,25\cdot28+0,25\cdot32+0,25\cdot39+0,25\)

\(=0,25\cdot\left(28+32+39+1\right)=0,25\cdot100=25\)

  4 giờ 45 phút 

+ 6 giờ 28 phút 

  10 giờ 73 phút   (73 phút = 1 giờ 13 phút)

hay 11 giờ 13 phút

  15 giờ 16 phút           đổi thành        14 giờ 76 phút

-  7 giờ 30 phút                                   - 7 giờ 30 phút

                                                              7 giờ 46 phút   

   \(\dfrac{1}{4}\) x 28 + 25% x 32 + \(\dfrac{25}{100}\) x 39 + 0,25

= 0,25 x 28 + 0,25 x 32 + 0,25 x 39 + 0,25 x 1

= 0,25 x (28 + 32 + 39 +1)

= 0,25 x 100

= 25                                                          

\(\frac{1}{4}\times45+0,25\times35+\frac{25}{100}\times19+25\%\)

\(=0,25\times45+0,25\times35+0,25\times19+0,25\times1\)

\(=0,25\times\left(45+35+19+1\right)\)

\(=0,25\times100\)

\(=25\)

lần sau bn vt dấu các phép tính ra nha, vt như nay khó đọc lắm ak

(600-X)x4=100x4

Chia cả 2 vế cho 4, ta được:

600-X=100

     X=600-100

     X=500

Vậy X=500

\(0,25+25\%\times55+\dfrac{1}{4}\times45-\dfrac{2}{8}\)

\(=\dfrac{1}{4}+\dfrac{1}{4}\times55+\dfrac{1}{4}\times45-\dfrac{1}{4}\)

\(=\dfrac{1}{4}\times\left(1+55+45-1\right)\)

\(=\dfrac{1}{4}\times100\)

\(=25\)

\(0,25+25\%\times55+\dfrac{1}{4}\times45-\dfrac{2}{8}\)

\(=\dfrac{1}{4}+\dfrac{1}{4}\times55+\dfrac{1}{4}\times45-\dfrac{1}{4}\)

\(=\dfrac{1}{4}\times1+\dfrac{1}{4}\times55+\dfrac{1}{4}\times45-\dfrac{1}{4}\times1\)

\(=\dfrac{1}{4}+\left(1+55+45-1\right)\)

\(=\dfrac{1}{4}\times100\)

\(=0,25\times100\)

\(=25\)

\(#:)\)

a,25/100 +19/22+19/35+3/4+3/22+16/35

=(19/22+3/22)+(19/35+16/35)+(25/100+3/4)

=   22/22 + 35/35 + ( 1/4 + 3/4)

= 22/22 + 35/35 + 4/4

= 1 + 1 + 1

= 3

b, 2/5 : 4/7 - 2/5 : 2/3

=(2/5 - 2/5) : (4/7 : 2/3)

= 0 : 6/7

=0

tất cả các số kia là đều phần hết

1) \(\frac{25}{100}+\frac{19}{22}+\frac{19}{35}+\frac{3}{4}+\frac{3}{22}+\frac{16}{35}\)

\(=\frac{1}{4}+\frac{19}{22}+\frac{19}{35}+\frac{3}{4}+\frac{3}{22}+\frac{16}{35}\)

\(=\left(\frac{1}{4}+\frac{3}{4}\right)+\left(\frac{19}{22}+\frac{3}{22}\right)+\left(\frac{19}{35}+\frac{16}{35}\right)\)

\(=1+1+1\)

\(=3\)

2) \(\frac{2}{5}:\frac{4}{7}-\frac{2}{5}:\frac{2}{3}\)

\(=\frac{2}{5}:\left(\frac{4}{7}-\frac{2}{3}\right)\)

\(=\frac{2}{5}:\frac{-2}{21}\)

\(=-\frac{21}{5}\)

=))

\(=\left(\frac{75}{100}+\frac{65}{100}+\frac{1}{4}+\frac{35}{100}\right)\left(\frac{1}{4}.2+\frac{25}{100}.3+\frac{25}{100}.5\right)\)

\(=\left(\frac{3}{4}+\frac{13}{20}+\frac{1}{4}+\frac{7}{20}\right)\left(\frac{2}{4}+\frac{3}{4}+\frac{5}{4}\right)\)

\(=\left(1+1\right).\frac{10}{4}\)

\(=2.\frac{5}{2}\)

\(=5\)