tính nhanh;
A)81+243+19
B)5.25.2.16.4
C)32.47+32.53
D) (1200+60):12
E)2.31.12+4.6.42+8.27.3
F)58.75+58.50-58.25
G) 3 ² ·65+3 ².35
H) (23.36-17.36):36
giúp mình với mai thi rồi
tính nhanh; A)81+243+19 B)5.25.2.16.4 C)32.47+32.53 D) (1200+60):12 E)2.31.12+4.6.42+8.27.3 F)58.75+58.50-58.25 G) 3 ² ·65+3 ².35 H) (23.36-17.
By Isabelle
Đáp án:a)
=(81+19)+243
=343
b)64.100
=6400
c)32.(47+53)
=3200
d)105
e)2400
f)5800
g)900
h)6
Giải thích các bước giải:
a,
`81+243+19`
`=(81+19)+243`
`=100+243`
`=243`
b,
`5.25.2.16.4`
`=(5.2).(25.4).16`
`=10.100.16`
`=16000`
c,
`32.47+32.53`
`=32.(47+53)`
`=32.100`
`=3200`
d,
`( 1200 + 60 ) : 12`
`= 1200 : 12 + 60 : 12`
`= 100 + 5`
`= 105`
e,
`2 . 31 . 12 + 4 . 6 . 42 + 8 . 27 . 3`
`= ( 2 . 12 ) . 31 + ( 4 . 6 ) . 42 + ( 8 . 3 ) . 27`
`= 24 . 31 + 24 . 42 + 24 . 27`
`= 24 . ( 31 + 42 + 27 ) `
`= 24 . 100`
`= 2400`
f,
`58 . 75 + 58 . 50 – 58 . 25`
`= 58 . ( 75 + 50 – 25 )`
`= 58 . 100`
`= 5800`
g,
`3^2 .65+3^2 .35`
`= 3^2 . ( 65 + 35 ) `
`= 9 . 100`
`= 900`
h,
`(23.36-17.36):36`
`= [( 23 – 17) . 36 ] : 36`
`= ( 6 . 36 ) : 36`
`= 6 . 36 : 36`
`= 6 . 1 `
`= 6`