a) 142 x 12 + 142 x 18

= 142 x ( 18 + 12 )

= 142 x 30

= 4260

b) 49 . 365 - 39 . 365

= 365 . ( 49 - 39)

= 365 . 10

= 3650

c) 4 . 18 . 25

= 18 . 4 . 25

= 18 . 100

= 1800

a, 142 x 12 + 142 x18=142 x (12+18)= 4260

b, 49 x 365 - 39 x356 = 356 x (49-39)= 3560

c,4 x 18 x 25 = (25 x 4) x 18=1800

\(a,142\times12+142\times18=142\times\left(12+18\right)=142\times30=4260\\ b,49\times365-39\times365=365\times\left(49-39\right)=365\times10=3965\\ c,4\times18\times25=\left(4\times25\right)\times18=100\times18=1800\)

a) 142 x 12 + 142 x 18

=142x(12+18)

=142x30

=4260

b) 49 x 365 - 39 x 365

=(49-39)x365

=10x365

=3650

c) 4 x 18 x 25

=4x25x18

=100x18

=1800

a) 142 x 12 + 42 x 18

= 142 x (12 +18)

= 142 x 30 = 4260

b) 49 x 365 - 39 x 365

= (49-39) x 365

= 10 x 365 = 3650

c) 4 x 18 x 25

= 18 x (4 x 25)

= 10 x 100 = 1800

TL:

a. 142 x 12 + 142 x 18

= 142 x (12 + 18)

= 142 x 30

= 4260

b. 49 x 365 - 39 x 365

= (49 - 39) x 365

= 10 x 365

= 3650

c. 4 x 18 x 25

= (4 x 25) x 18

= 100 x 18

= 1800

HT

Tính bằng cách thuận tiện nhất:

a) 142 x 12 + 142 x 18

= 142 x ( 12 + 18 ) 

= 142 x 30

= 4260

b) 49 x 365 - 39 x 365

= ( 49 - 39 ) x 365

= 10 x 365 

= 3650 

c) 4 x 18 x 25

= ( 4 x 25 ) x 18 

= 100 x 18 

= 1800

a) 142 x 12 + 42 x 18 = 142 x (12 +18) = 142 x 30 = 4260

b) 49 x 365 – 39 x 365 = (49-39) x 365 = 10 x 365 = 3650

c) 4 x 18 x 25 = 18 x (4 x 25) = 10 x 100 = 1800

_k me_

@Min_ngu_ngục

_copy is not  fun_

Tính bằng cách thuận tiện nhất :

a) 146 x 12 + 142 x 18

b) 49 x 365 - 39 x 365

c) 4 x 18 x 25

Bài giải

a) 142 x 12 + 142 x 18 = 142 x (12 + 18) = 142 x 30 = 4260

b) 49 x 365 – 39 x 365 = (49 – 39) x 365 = 10 x 365 = 3650

c) 4 x 18 x 25 = (4 x 25) x 18 = 100 x 18 = 1800

Chúc bạn học tốt nha!

=142x(12+18)

=142x30

=4260

142 x 12+ 142 x 18 = ( 12 + 18) x 142 = 30 x 142 = 4260

49 x 365 - 39 x 365 = ( 49 - 39) x 365 = 10 x 365 = 3650

4 x 18 x 25= ( 4 x 25) x 18 = 100 x 18 = 1800

Bài 2: Tính bằng cách thuận tiện nhất

\(\text{a. 1255 + 436 + 145}\)

\(=\left(1255+145\right)+436\)

\(=1400+436\)

\(=1836\)

\(\text{b. 142 x 12 + 142 x 18}\)

\(=142\times\left(12+18\right)\)

\(=142\times30\)

\(=4260\)

\(\text{c. 4 x 18 x 25}\)

\(=\left(25\times4\right)\times18\)

\(=100\times18\)

\(=1800\)

Bài 2:

a: \(=1400+436=1836\)

b: =142(12+18)

=142*30

=4260

c: \(=100\cdot18=1800\)

Bài 3:

a: \(41m^219dm^2>409dm^2\)

b: \(90000cm^2< 90m^2\)

c: \(30m^26dm^2< 3060dm^2\)

d: \(8012cm^2>8dm^212cm^2\)

e: \(5dm^29cm^2=509cm^2\)

f: \(3940dm^2=39m^240dm^2\)

g: \(300m^26dm^2>3006dm^2\)

h: \(2009cm^2< 21dm^2\)

Bài 1:

a)345x200=69000           b)237x24=5688              c)403x346=139438

Bài 2:

a)95+11x206=2361       b)95x11+206=2361                  c)95x11x206=215270

1.

a) 69000; b) 5688; c) 139438

2.

a) 2361;b) 1251;c) 215270

3.

a) 2460

b) 3650

c) 1800

Câu 10:

\(a,y\times7+y\times3=70\\ \Rightarrow y\times\left(7+3\right)=70\\ \Rightarrow y\times10=70\\ \Rightarrow y=7\\ b,18:y+12:y=3\\ \Rightarrow\left(18+12\right):y=3\\ \Rightarrow30:y=3\\ \Rightarrow y=10\)

câu 11:

\(a,9\times365+2\times365-365=\left(9+2-1\right)\times365=10\times365=3650\\ b,108:9-18:9=\left(108-18\right):9=90:9=10\\ c,43\times95+4\times43+43=43\times\left(95+4+1\right)=43\times100=4300\)