0,025 x 628 + 36,2 x 25% + \(\frac{1}{4}\)

= 0,025 x 10 x 62,8 + 36,2 x \(\frac{1}{4}\)+ \(\frac{1}{4}\)

= \(\frac{1}{4}\) x 62,8 + 36,2 x \(\frac{1}{4}\)+ \(\frac{1}{4}\)

= \(\frac{1}{4}\)x ( 62,8 + 36,2 + 1 )

= \(\frac{1}{4}\)x 100

= 25

a: =300

e: =17500

a) 25.12

= 25.(10+2)

= 25.10+25.2

=250+50

=300

Bạn cứ áp dụng vào để tính những câu còn lại nhé! 

a=247,75

là đ/s

A = 0,025 x 628 + 36,2 x 25% + \(\frac{1}{4}\)

A = 0,25 x 628 : 100  + 36,2 x 0,25 + 0,25

A = 0,25 x 62,8 + 36.2 x 0,25 + 0,25 x 1

A = 0,25 x ( 62,8 + 36,2 + 1 )

A = 0,25 x 100

A = 25

a) \(\dfrac{7}{9}\times\dfrac{13}{25}\times\dfrac{9}{7}=\left(\dfrac{7}{9}\times\dfrac{9}{7}\right)\times\dfrac{13}{25}=1\times\dfrac{13}{25}=\dfrac{13}{25}\)

b) \(\dfrac{5}{9}\times\dfrac{21}{25}+\dfrac{21}{25}\times\dfrac{4}{9}\)

\(=\dfrac{21}{25}\times\left(\dfrac{5}{9}+\dfrac{4}{9}\right)\)

\(=\dfrac{21}{25}\times1=\dfrac{21}{25}\)

c) \(\dfrac{19}{5}\times\dfrac{11}{16}-\dfrac{9}{5}\times\dfrac{11}{16}\)

\(=\dfrac{11}{16}\times\left(\dfrac{19}{5}-\dfrac{9}{5}\right)\)

\(=\dfrac{11}{16}\times2=\dfrac{22}{16}=\dfrac{11}{8}\)

a) 12,4 x 72,53 + 27,47 x 12,4

= 12,4×(72,53+27,47)

=12,4×100

=1240

cám ơn 

\(1,\\ c,\dfrac{17}{6}-\dfrac{3}{7}-\dfrac{5}{6}=\dfrac{17\times7-3\times6-5\times7}{6\times7}=\dfrac{119-18-35}{42}=\dfrac{66}{42}=\dfrac{11}{7}\\ 2,\\ a,\dfrac{6}{9}+\dfrac{3}{15}+\dfrac{7}{15}\\ =\dfrac{6:3}{9:3}+\dfrac{7+3}{15}\\ =\dfrac{2}{3}+\dfrac{10}{15}\\ =\dfrac{2}{3}+\dfrac{2}{3}\\ =\dfrac{2+2}{3}=\dfrac{4}{3}\)

\(b,\dfrac{7}{2}+\dfrac{29}{12}-\dfrac{11}{12}\\ =\dfrac{7}{2}+\left(\dfrac{29}{12}-\dfrac{11}{12}\right)\\ =\dfrac{7}{2}+\dfrac{29-11}{12}\\ =\dfrac{7}{2}+\dfrac{18}{12}\\ =\dfrac{7}{2}+\dfrac{18:6}{12:6}\\ =\dfrac{7}{2}+\dfrac{3}{2}\\ =\dfrac{7+3}{2}=\dfrac{10}{2}=5\)

\(c,\dfrac{26}{25}-\dfrac{3}{5}-\dfrac{2}{5}\\ =\dfrac{26}{25}-\dfrac{3\times5}{5\times5}-\dfrac{2\times5}{5\times5}\\ =\dfrac{26-15-10}{25}\\ =\dfrac{1}{25}\)

Bài 1:
\(\dfrac{17}{6}-\dfrac{3}{7}-\dfrac{5}{6}=\left(\dfrac{17}{6}-\dfrac{5}{6}\right)-\dfrac{3}{7}=2-\dfrac{3}{7}=\dfrac{14}{7}-\dfrac{3}{7}=\dfrac{11}{7}\)
Bài 2:
a/\(\dfrac{6}{9}+\dfrac{3}{15}+\dfrac{7}{15}\)
\(=\dfrac{2}{3}+\left(\dfrac{3}{15}+\dfrac{7}{15}\right)\)
\(=\dfrac{2}{3}+\dfrac{2}{3}\)
\(=\dfrac{4}{3}\)
b/\(\dfrac{7}{2}+\dfrac{29}{12}-\dfrac{11}{12}\)
\(=\dfrac{7}{2}+\left(\dfrac{29}{12}-\dfrac{11}{12}\right)\)
\(=\dfrac{7}{2}+\dfrac{3}{2}\)
\(=5\)
c/\(\dfrac{26}{25}-\dfrac{3}{5}-\dfrac{2}{5}\)
\(=\dfrac{26}{25}-\left(\dfrac{3}{5}+\dfrac{2}{5}\right)\)
\(=\dfrac{26}{25}-1\)
\(=\dfrac{26}{25}-\dfrac{25}{25}\)
\(=\dfrac{1}{25}\)
#Đang Bận Thở

264,14 : 0,25 : 4

= 264,14 : ( 0,25 x 4 )

= 264,14 : 1

= 264,14 

36,45 : 0,2 x 2 : 5

=  36,45 : ( 2 x 5 ) : 0,2

= 36,45 : 10 : 0,2 

= 3,645 : 0,2

= 18,225

`#040911`

`a)`

`27 \times 38 + 62 \times 27 - 27 \times 90`

`= 27 \times (38 + 62 - 90)`

`= 27 \times (100 - 90)`

`= 27 \times 10`

`= 270`

\(27\times38+62\times27-27\times90\)

\(=27\times\left(38+62-90\right)\)

\(=27\times\left(100-90\right)\)

\(=27\times10\)

\(=270\)

a) 1 267 + 99 + 501 = 1 267 + (99 + 501)

                                = 1 267 + 600 = 1 867

     25 x 14 x 4 = (25 x 4) x 14

                       = 100 x 14 = 1 400

b) 3 905 x (50 – 1) = 3 905 x 50 – 3 905 x 1

                             = 195 250 – 3 905 = 191 345

     270 : ( 27 x 2 ) = 270 : 27 : 2

                             = 10 : 2 = 5

c) 115 x 58 + 115 x 42 = 115 x (58 + 42)

                                   = 115 x 100 = 11 500

136 x 67 – 136 x 66 = 136 x (67 – 66)

                              = 136 x 1 = 136