\(\frac{167}{99}\)

c) 5 . 25 . 2 . 16 . 4 = (5 . 2)(25.4) . 16 = 10 . 100. 16 = 16000

a). 25.5.4.27.2=(25.4).(5.2).27=100.10.27=1000.27=27000

b). 28.64+28.36=28.(64+36)=28.100=2800

a=457

b=269

d=57

còn câu C ko có phép tính nên mình ko làm

a) 86+357+14=(86+14)+357=100+357=457

b) 72+69+128=(72+128)+69=200+69=269

c) 25.5.4.27.2=(25.4).(5.2).27=100.10.27=27000

d) 28.64+28.36=28.(64+36)=28.100=2800

Tomoyo Daidouji à phép nhân á bạn . 25 nhân 5 nhân 4 nhân 27 nhân 2

a ) 17 x 4 = ( 15 + 2 ) x 4 = 15 x 4 + 2 x 4 = 60 + 8 = 68

      25 x 28 = 25 x ( 20 + 8 ) = 25 x 20 + 25 x 8 = 500 + 200 = 700

b ) 13 x 12 = 13 x ( 10 + 2 ) = 13 x 10 + 13 x 2 = 130 + 26 = 156

      53 x 11 = 53 x ( 10 + 1 ) = 53 x 10 + 53 x 1 = 530 + 53 = 583

      39 x 101 = 39 x ( 100 + 1 ) = 39 x 100 + 39 x 1 = 3900 + 39 = 3939

a) Ta có:

\(17\times4=\left(15+2\right)\times4=15\times4+2\times4=60+8=68\)

\(25\times28=25\times\left(20+8\right)=25\times20+25\times8=500+200=700\)

b) Ta có:

\(13\times12=13\times\left(10+2\right)=13\times10+13\times2=130+26=156\)

\(53\times11=53\times\left(10+1\right)=53\times10+53\times1=530+53=583\)

\(39\times101=39\times\left(100+1\right)=39\times100+39\times1=3900+39=3939\)

25 x 28

= 25 x 4 x 7

= (25 x 4) x 7

= 100 x 7

= 700

\(35x4=\left(25+15\right)x4=100+60\)\(=160\)

\(25x36=25x4x9=100x9=900\)

\(35\times4=140\)

\(25\times36=900\)

\(36\times12=432\)

\(75\times11=825\)

\(67\times101=6767\)

2 cách mà sao mg làm có 1 cách vậy.

Áp dụng các tính chất của phép cộng và phép nhân để tính nhanh:

a) 81 + 243 + 19

= ( 81 + 19 ) + 243

= 100 + 243

= 343

b) 168 + 79 + 132

= ( 168 + 132 ) + 79

= 300 + 79

= 379

c) 5 . 25 . 2 . 16 . 4

= ( 5 . 2 ) . ( 25 . 4 ) . 16

= 10 . 100 . 16

= 1000 . 16

= 16000

d) 32 . 47 + 32 . 53

= 32 . ( 47 + 53 )

= 32 . 100

= 3200

a) 81 + 243 + 19

    =(81+19)+243

    =100+243

     =343

b) 168 + 79 + 132

=(168+132)+79

=200+79

=279

c) 5 . 25 . 2 . 16 . 4

=(5.2).(25.4).16

=10.100.16

=16000

d) 32 . 47 + 32 . 53

=32.(47+53)

=32.100

=3200.

a) 81+243+19

=(81+19)+243

=100+243

=343

b) 168+79+132

=(168+132)+79

=300+79

=379

c) 5.25.2.16.4 

= (5.2) . (25.4) . 16

=10.100.16

=16000

d) 32.47+32.53 

=32. (47+53)

=32.100

=3200

a)17.25=25.17=25.(1+16)=25.1+25.16=25+25.4.4=25+100.4=25+400=425

b)281+129+219=281+219+129=500+129=629

c)2³.2²+5⁵:5³=2³⁺²+5^5-3=2⁵+5²=32+25=57

d)29.31+66.69+31.37=31.(29+37)+66.69=31.66+66.69=66.(31+69)=66.100=6600

a. 17.25 = 425

b. 281+129+219 = (281 + 219) + 129 = 500 + 129 = 629

c. 2³.2²+5⁵:5³ = 2⁵+5²=32+25=57

d. 29.31+66.69+31.37

= 29.31+31.37+66.69

= 31.(29+37)+66.69

= 31.66+66.69

= 66.(31 + 69)

= 66.100

= 6600

a)17.25=425

b)281+129+219=(281+219)+129=1000+129=1129

c)2^3.2^2+5^5:5^3=2^(3+2) +5^(5-3)=2^5+5^2=32+25=57

d)29.31+66.69+31.37=31(29+37)+66.69=31.66+66.69=66(31+69)=66.100=3100