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\(A=\frac{1}{2}+\frac{1}{14}+\frac{1}{35}+\frac{1}{65}+\frac{1}{104}+\frac{1}{152}=>\frac{1}{2}A=\frac{1}{4}+\frac{1}{28}+\frac{1}{70}+...+\frac{1}{304}\)
\(=\frac{1}{1.4}+\frac{1}{4.7}+\frac{1}{7.10}+...+\frac{1}{16.19}=\frac{1}{3}.\left(\frac{3}{1.4}+\frac{3}{4.7}+...+\frac{3}{16.19}\right)=\frac{1}{3}.\left(1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+...+\frac{1}{16}-\frac{1}{19}\right)=\frac{1}{3}.\left(1-\frac{1}{19}\right)=\frac{1}{3}.\frac{18}{19}=\frac{6}{19}\)=> A= \(\frac{6}{19}:\frac{1}{2}=\frac{12}{19}\)
đúng nha
4,25.58,47-125+41,53.4,25
= 4,25.58,47+41,53.4,25-125
= 4,25.(58,47+41,53)-125
= 425-125
= 300
4,25.58,47-125+41,53.4,25
=4,25.(58,47+41,53)-125
=4,25.100-125
=425-125=300
234456
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123798
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110658
ĐÂY NHÉ !!! ĐÚNG CHO MK LIKE NHEN !!!
B) 42.53+47.156-47.114
=42.53+47(156-114)
=42.53+47.42
=42(53+47)
=42.100
=4200
341.67+341.6+659.83
=341.(67+6)+659.83
=341.83+659.83
=(341+659).83
=1000.83
=83000.
42.53+47.156-47.114
=42.53+47.(156-114)
=42.53+47.42
=42.(53+47)
=42.100.
NẾU ĐÚNG THÌ K OK OK OK OK
=4200
L = 2015 . 102
= 2015 x 100 + 2015 x 2
= 201500 + 4030
= 205530
M = 998 x 45
= 1000 x 45 - 2 x 45
= 45000 - 90
= 44910
L = 2015 . 102
= 2015 x 100 + 2015 x 2
= 201500 + 4030
= 205530
M = 998 x 45
= 1000 x 45 - 2 x 45
= 45000 - 90
= 44910
