tính nhanh: -311 + 2 X 312
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`2 1/2 xx 7/5 + (-9/10) xx 2/3`
`= 5/2 xx 7/10 + (-9/10) xx 2/3`
`= 35/20 + (-18/30)`
`= 7/4 + (-3/5)`
`= 23/20`
__
`x + 45% =2 1/2 - 5/3`
`=> x+ 45/100 = 5/2 - 5/3`
`=>x+ 9/20= 15/6-10/6`
`=> x+9/20 = 5/6`
`=>x= 5/6 - 9/20`
`=>x=23/60`
__
`80% +x=-5/2 +3/4`
`=> 80/100 + x= -10/4 +3/4`
`=> 4/5 + x= -7/4`
`=>x= -7/4-4/5`
`=>x=-51/20`
__
`4/25 -x=-5/2 +(-3/10)`
`=> 4/25 -x= -25/10 +(-3/10)`
`=> 4/25 -x= -28/10`
`=>x= 4/25 -(14/5)`
`=>x= 4/25 + 14/5`
`=>x=74/25`
\(312\times425+312\times574+312\)
\(=312\times\left(425+574+1\right)\)
\(=312\times1000\)
\(=312000\)
312 × 425 + 312 × 574 + 312
= 312 × (425 + 574 + 1)
= 312 × 1000
= 312000
Bài 2:
a) 37 x 7 - 17 x 11 + 13 x 37 + 17 x 21
b) 55 x 52 : 54 - 28 : 24
c) 311 x 12 + 312 x 5 - 314
`#040911`
`a)`
\(37 \times 7 - 17 \times 11 + 13 \times 37 + 17 \times 21\)
`= 37 \times (7 + 13) + 17 \times (21 - 11)`
`= 37 \times 20 + 17 \times 10`
`= 10 \times (37 \times 2 + 17)`
`= 10 \times 91`
`= 910`
`b)`
\(5^5 \times 5^2 \div 5^4 - 2^8 \div 2^4\)
`=`\(5^{5+2-4}-2^{8-4}\)
`= 5^3 - 2^4`
`= 125 - 16`
`= 109`
`c)`
\(3^{11}\times12+3^{12}\times5-3^{14}\)
`=`\(3^{11}\times\left(12+3\times5-3^3\right)\)
`=`\(3^{11}\times\left(12+15-27\right)\)
`=`\(3^{11}\times0=0\)
a) = 259 - 187 + 481 + 357
= 910
b) = 57 : 54 - 24
= 53 - 24
= 125 - 16
= 109
a)|x|<8
=>|x| E {0;1;2;3;4;5;;6;7}
=>x E {0;-1;1-2;2;-3;3;-4;4;-5;5;-6;6;-7;7}
b)2009+[312+(-2009)+(-312)]
=2009+312+(-2009)+(-312)
=[2009+(-2009)]+[312+(-312)]=0+0=0
tick đi
Lời giải:
1. Bạn coi lại đề
2. $=234\times (1257-257)=234\times 1000=234000$
3. $=175\times (1274-273-1)=175\times 1000=175000$
4. $=(4\times 25)\times (125\times 8)=100\times 1000=100000$
= 312 x 725 x 2 + 725 x 376
= 312 x 2 x 725 + 725 x 376
= 624 x 725 + 725 x 376
= 725 x (624 + 376)
= 725 x 1000
= 725000
tk mik đi
2x3-623x2-310x-614
=2.3123-623.3122-310.312-614
=(2.312-623)3122-310.312-614
=3122-310.312-614
=312(312-310)-614
=312.2-614=624-614=10
10.213
11. 2 giờ 55 phút
12. 4 ngày 21 giờ
13.
a: 6,008
b: 4500
c: 5,628
d: 4,009
14.
a,8579 cm2
b,32,04 m2
c,187200m2
d,5,017 tấn
14:
a: \(85.79km^2=857900000000cm^2\)
b: \(32m^24dm^2=32.04m^2\)
c: \(1872dm^2=18.72m^2\)
d: 5 tấn 17kg=5,017 tấn
13:
a: \(6dm^38cm^3=6.008dm^3\)
b: \(4.5m^3=4500dm^3\)
c: \(5628dm^3=5.628m^3\)
d: \(4m^39dm^3=4.009m^3\)
12: =108h:3+80h
=36h+80h=116h
10:
3h18p+7h21p:3
=198p:441p:3
=198p+147p=345p
\(-3^{11}+2.3^{12}\)
\(=-3^{11}+3^{11}.6\)
\(=-3^{11}\left(1-6\right)\)
\(=5.-3^{11}\)