Bài 2: Tính bằng cách thuận tiện nhất
a. 1255 +436 +145
b. 142 x 12 +142 x 18
c. 4 x 18 x 25
.............................................................................................................................. .............................................................................................................................. ..............................................................................................................................
.............................................................................................................................. .............................................................................................................................. .............................................................................................................................. Bài 3: > < =
41m2 19dm2 … 409dm2 30m2 6dm2 … 3060dm2 5dm2 9cm2 … 509cm2 300m2 6dm2 … 3006dm2 giúp vs ạ | 90 000cm2 … 90m2 8012cm2 … 8dm2 12cm2 3940dm2 … 39m2 40dm2 2009cm2 … 21dm2 |
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: \(2009cm^2< 21dm^2\)
