a, 1+2+3+4+5+6+7+8+9+...+100
b, 23+54+32+67+100x0
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`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) 67+135+33
= ( 67+33)+135
= 100 + 135
= 235
b) 146+121+54+379
= ( 146+54)+( 121+379)
= 200 + 500
= 700
c) 198+232-98-32
= ( 232-32)+(198-98)
= 200 + 100
= 300
d)1+2+3+4+.........+50
= ( 50+1) x 50:2 =1275
e)2+4+6+8+..........+100
= ( 100+2) x 50 : 2 =2550
f) 23 x 56 +56
= 1288 + 56
= 1344
g)32 x 19+32
= 608 + 32
= 640
\(a.67+135+33\)
\(=\left(67+33\right)+135\)
\(=100+135=235\)
\(b.141+121+54+379\)
\(=\left(146+54\right)+\left(121+379\right)\)
\(=200+500=700\)
\(c.198+232-98-32\)
\(=\left(232-32\right)+\left(198-98\right)\)
\(=200+100=300\)
\(f.23.56+56=1288+56=1344\)
\(g.32.19+32=608+32=640\)
uhuhyuiyyugyubvty
a, 1+2+3+4+5+6+7+8+9+...+100
Tổng dãy số trên là :
\(\frac{100.\left(100+1\right)}{2}=5050\)
b, 23+54+32+67+100x0
= 23 + 54 + 32 + 67
= ( 23 + 67 ) + ( 54 + 32 )
= 90 + 86
= 176
Study well