Tính nhanh
a) ( 7.29+9.34+8.27)-(7.34+6.27+5.29)
b)45.7×101-45.7
c) 50-51+40-41+30-31+60
d) 28+62×a×(a×1-a:1)+28×8+28
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a) ( 200 - 58 ) x 58 + ( 100 + 42 ) x 42
= 142 x 58 + 142 x 42
= 142 x ( 58 + 42 )
= 142 x 100
= 14200
b) 50 - 51 + 40 - 41 + 30 - 31 + 60
= ( 50 + 40 + 30 ) - ( 51 + 41 + 31 ) + 60
= 120 - 123 + 60
= -3 + 60
= 57
caau b ko chắc
c) 28 + 62 x a x ( a x1 trừ a : 1 ) cộng 28 x 8 cộng
= 28 + 62a x 0 + 28 x 8
= 28 x 1 + 0 + 28 x 8
= 28 x ( 1 + 8 )
= 28 x 9
= 252
`a,`
`31/23-(7/32+8/23)`
`=31/23-7/32-8/23`
`=(31/23-8/23)-7/32`
`=1-7/32=25/32`
`b,`
`38/45-(8/45-17/51-3/11)`
`=38/45-8/45+17/51+3/11`
`= (38/45-8/45)+17/51+3/11`
`=2/3+17/51+3/11`
`=1+3/11=14/11`
`c,`
`(1/3+12/67+13/41)-(79/67-28/41)`
`= 1/3+12/67+13/41-79/67+28/41`
`= 1/3+(12/67-79/67)+(13/41+28/41)`
`= 1/3+(-1)+1=1/3+(-1+1)=1/3+0=1/3`
`d,`
`1/5+(-1/6)+1/7+(-1/8)+1/9+1/8+(-1/7)+1/6+(-1/5)`
`= (1/5+ -1/5)+(-1/6+1/6)+(1/7+ -1/7)+(-1/8 +1/8)+1/9`
`= 0+0+0+0+1/9=1/9 .`
\(a\frac{31}{23}-\left(\frac{7}{23}+\frac{8}{23}\right)\)
\(=\frac{31}{23}-\frac{7}{23}-\frac{8}{23}\)
\(=\frac{16}{23}\)
Hot
tốt
!
a)\(\frac{31}{23}-\left(\frac{7}{23}+\frac{8}{23}\right)=\frac{31}{23}-\frac{8}{23}+\frac{7}{23}=1+\frac{7}{23}=1\frac{7}{23}\)
b)\(\left(\frac{1}{3}+\frac{12}{67}+\frac{13}{41}\right)-\left(\frac{79}{67}-\frac{28}{41}\right)=\left(\frac{13}{41}+\frac{28}{41}\right)+\left(\frac{79}{67}-\frac{12}{67}\right)-\frac{1}{3}=1+1-\frac{1}{3}\)
\(=2-\frac{1}{3}=\frac{5}{3}\)
Trả lời
b)(1/3+12/67+13/41)-(79/67-28/41)
=1/3+12/67+13/41-79/67+28/41
=1/3+(12/67-79/67)+(13/41+28/41)
=1/3+(-67/67)+41/41
=1/3+(-1)+1
=1/3+0
=1/3.
a) \(\left(7,29+9,34+8,27\right)-\left(7,34+6,27+5,29\right)\)
\(=\left(7,29-5,29\right)+\left(9,34-7,34\right)+\left(8,27-6,27\right)\)
\(=2+2+2\)
\(=6\)
b ) \(45,7\times101-45,7\)
\(=45,7\times101-45,7\times1\)
\(=45,7\times\left(101-1\right)\)
\(=45,7\times100\)
\(=457\)
c ) \(50-51+40-41+30-31+60\)
\(=\left(60-51\right)+\left(50-41\right)+\left(40-31\right)+30\)
\(=9+9+9+30\)
\(=57\)
d ) \(28+62\times a\times\left(a\times1-a\div1\right)+28\times8+28\)
\(=28+62\times a\times\left(a-a\right)+28\times8+28\times1\)
\(=28\times1+62\times a\times0+28\times8+28\times1\)
\(=28\times1+0+28\times8+28\times1\)
\(=28\times\left(8+1+1\right)\)
\(=280\)
\(a,7.29+9.34+8.27-7.34-6.27+5.29\)
\(=2+2+2=6\)
\(b,45.7x101-45.7x1\)
\(=45.7x\left(101-1\right)\)
\(=45.7x100=4570\)
\(c,50+40+30+60-51-41-31\)
\(=180-51-41-31\)
\(=129-41-31=88-31=57\)