a) 8,65 + 7,6 + 1,35 + 0,4 

= ( 8,65 + 1,35) + ( 7,6 + 0,4 )

= 10 + 8

=18.

b) 5,92 + 0,44 + 5,56 + 4,08

= ( 5,92 + 4,08 ) + ( 0,44 + 5,56 )

= 10 + 6

= 16.

k mik nhé!!

#Học tốt.

\(a.8,65+7,6+1,35+0,4\)

\(=\left(8,35+1,35\right)+\left(7,6+0,4\right)\)

\(=10+8=18\)

\(b.5,92+0,44+5,56+4,08\)

\(=\left(5,92+4,08\right)+\left(0,44+5,56\right)\)

\(=10+6=16\)

12,35 + 1,42 - 11,35 + 8,58

= (12,35 - 11,35) + (1,42 + 8,58)

= 1 + 10

= 11

12,35 + 1,42 - 11,35 + 8,58 
= 12,35 + (1,42 - 11,35 ) + 8,58 
= 12,35 - 9,93 + 8,58 
= 2,42 + 8,58 
= 11

370x101

=370 x (100 + 1)

= 370 x 100 + 370 x 1

= 37000 + 370

= 37370

Chúc bạn học tốt

370 x ( 100 +1) = 370 x 100 + 370 x 1 = 37000 + 370 = 37370

\(0,12\times400\)
\(\Rightarrow0,12\times100\times4\)
\(\Rightarrow12\times4\)
\(\Rightarrow48\)

0,12 x 400 = 48

Bài 1:
$539,6+73,495= 613,095$

$247,06+316,492=613,095$

$8,9+9,3+4,7+5=27,9$

$324,8+66,7+208,4=599,9$

Bài 2:

a.

$=(8,65+1,35)+(7,6+0,4)=10+8=18$

b.

$=(5,92+4,08)+(0,44+5,56)=10+6=16$

c.

$=(7,5+2,5)+(6,5+3,5)+(5,5+4,5)=10+10+10=30$

d.

$=(1,2+7,8)+(2,3+6,7)+(3,4+5,6)+4,5=9+9+9+4,5$

$=27+4,5=31,5$

Tính bằng cách thuận tiện nhất:

8,65+7,6+1,35+0,4=(7,6+0,4)+(8,65+1,35)

                                 =8+10=18

8,24+3,69+2,31=8,24+(3,69+2,31)

=8,24+6

=13,24

Tìm x:

X+362,7=61,8×7,9

X+362,7=488,22

X=488,22-362,7

X=125,52

Biểu thức:

21,537×31,4+42,1×21,537+21,537×26,5

=21,537×(31,4+42,1+26,5)

=21,537×100

=2153,7

\(8,65+7,6+1,35+0,4\)

\(=\left(8,65+1,35\right)+\left(7,6+0,4\right)\)

\(=10+8\)

\(=18\)

\(8,24+3,69+2,31\)

\(=8,24+\left(3,69+2,31\right)\)

\(=8,24+6\)

\(=14,24\)

\(X+362,7=61,8x7,9\)

\(X=61,8x7,9-362,7\)

\(X=488,22-362,7\)

\(X=125,52\)

\(21,537x31,4+42,1x21,357+21,357x26,5\)

\(=21,357x\left(31,4+42,1+26,5\right)\)

\(=21,357x100\)

\(=2135,7\)

Chúc bạn học tốt !!! 

\(=0,18\left(0,2\cdot950+1\right)+3\left(242\cdot2+3\right)=1495,38\)

\(=0,18\left(0,2\cdot950+1\right)+3\left(242\cdot2+3\right)=1495,38\)

chị ơi, em tính máy là 1797,18 cơ ạ 

Ta có: 0,15x400

=0,15 x 4 x 100= 0,6 x 100=60

0,15 x 400 = 0,15 x 100 x 4 

                  = 15 x 4

                   = 60

\(7,28\div0,25+7,28\times5+7,28\)

\(=7,28\times4+7,28\times5+7,28\times1\)

\(=7,28\times\left(4+5+1\right)\)

\(=7,28\times10\)

\(=72,8\)