a) = 1/2 + 1/3 = 5/6
b) = 2/5 + 2/3 = 16/15
c) = 7/11 . ( 3/4 + 1/4 ) + 4/11
= 7/11 . 1 + 4/11
= 7/11 + 4/11
= 1
d) = ( 3/4 + 1/2 + 1/4 ) . 8/3
= 3/2 . 8/3
= 4
Câu 1.
a) 1-\(\dfrac{1}{2}\)+\(\dfrac{1}{3}\)= \(\dfrac{1}{2}\)+\(\dfrac{1}{3}\)=\(\dfrac{3}{6}\)+\(\dfrac{2}{6}\)=\(\dfrac{5}{6}\)
b) \(\dfrac{2}{5}\)+\(\dfrac{3}{5}\):\(\dfrac{9}{10}\)= 1 :\(\dfrac{9}{10}\)= \(\dfrac{10}{9}\)
c) \(\dfrac{7}{11}\).\(\dfrac{3}{4}\)+\(\dfrac{7}{11}\).\(\dfrac{1}{4}\)+\(\dfrac{4}{11}\)=\(\dfrac{7}{11}\).1+\(\dfrac{4}{11}\)=1
a) \(1-\dfrac{1}{2}+\dfrac{1}{3}=\left(1-\dfrac{1}{2}\right)+\dfrac{1}{3}\)
\(=\dfrac{1\cdot2-1}{2}+\dfrac{1}{3}\)
\(=\dfrac{1}{2}+\dfrac{1}{3}\)
\(=\dfrac{3}{6}+\dfrac{2}{6}\)
\(=\dfrac{5}{6}\)
b) \(\dfrac{2}{5}+\dfrac{3}{5}:\dfrac{9}{10}=\dfrac{2}{5}+\dfrac{3}{5}\cdot\dfrac{10}{9}\)
\(=\dfrac{2}{5}+\dfrac{3\cdot10}{5\cdot9}\)
\(=\dfrac{2}{5}+\dfrac{3\cdot5\cdot2}{5\cdot3\cdot3}\)
\(=\dfrac{2}{5}+\dfrac{2}{3}\)
\(=\dfrac{6}{15}+\dfrac{10}{15}\)
\(=\dfrac{16}{15}\)
c) \(\dfrac{7}{11}\cdot\dfrac{3}{4}+\dfrac{7}{11}\cdot\dfrac{1}{4}+\dfrac{4}{11}=\dfrac{7}{11}\cdot\left(\dfrac{3}{4}+\dfrac{1}{4}\right)+\dfrac{4}{11}\)
\(=\dfrac{7}{11}\cdot1+\dfrac{4}{11}\)
\(=\dfrac{7}{11}+\dfrac{4}{11}\)
\(=1\)
d) \(\left(\dfrac{3}{4}+0,5+25\%\right)\cdot2\dfrac{2}{3}=\left(\dfrac{3}{4}+0,5+25\%\right)\cdot\dfrac{2\cdot3+2}{3}\)
\(=\left(\dfrac{3}{4}+0,5+25\%\right)\cdot\dfrac{8}{3}\)
\(=\left[\left(\dfrac{3}{4}\cdot100\%\right)+\left(0,5\cdot100\%\right)+25\%\right]\cdot\dfrac{8}{3}\)
\(=\left(75\%+50\%+25\%\right)\cdot\dfrac{8}{3}\)
\(=\dfrac{75+50+25}{100}\cdot\dfrac{8}{3}\)
\(=\dfrac{150}{100}\cdot\dfrac{8}{3}\)
\(=\dfrac{150\cdot8}{100\cdot3}\)
\(=\dfrac{5\cdot3\cdot10\cdot4\cdot2}{5\cdot2\cdot10\cdot3}\)
\(=4\)
Sau khi giảm giá, giá của 1 quyển tập là:
7000 - (7000 : 100 . 10) = 6300 (đồng)
Số tiền mua 15 quyển tập là:
6300 . 15 = 94500 (đồng)
Vậy: bạn An đủ tiền để mua 15 quyển tập và còn dư 5500 đồng.
Chúc học tốt!
a) 1- 1/2 + 1/3 = 6/6 - 3/6 + 2/6 = 5/6 b) 2/5 + 3/5 : 9/10 = 2/5 + 3/5 . 10/9 = 2/5 + 2/3 = 16/15 c) = 7/11 . (3/4 + 1/4) + 4/11 = 7/11 . 1 + 4/11 = 7/11 + 4/11 = 1 d) = (3/4 + 1/2 + 1/4) . 8/3 = 3/2 . 8/3 = 1/1 . 4/1 4
a) 1−12+13=6−3+26=561−12+13=6−3+26=56.
b) 25+35:910=25+35⋅109=25+23=161525+35:910=25+35⋅109=25+23=1615.
c) 711⋅34+711⋅14+411=711(34+14)+411=711+411=1711⋅34+711⋅14+411=711(34+14)+411=711+411=1.
d) (34+0,5+25%)⋅223=(34+12+14)⋅83=32⋅83=4(34+0,5+25%)⋅223=(34+12+14)⋅83=32⋅83=4.
a) 1/2 + 1/3 = 5/6
b) 2/5 + 2/3 = 16/15
c) 7/11 . ( 3/4 + 1/4) + 4/11 = 1
d) (3/4 + 1/2 + 1/4). 8/3 = 3/2. 8/3 = 4
a) 1−12+13=6−3+26=561−12+13=6−3+26=56.
b) 25+35:910=25+35⋅109=25+23=161525+35:910=25+35⋅109=25+23=1615.
c) 711⋅34+711⋅14+411=711(34+14)+411=711+411=1711⋅34+711⋅14+411=711(34+14)+411=711+411=1.
d) (34+0,5+25%)⋅223=(34+12+14)⋅83=32⋅83=4(34+0,5+25%)⋅223=(34+12+14)⋅83=32⋅83=4.
a) 1−12+13=6−3+26=561−12+13=6−3+26=56.
b) 25+35:910=25+35⋅109=25+23=161525+35:910=25+35⋅109=25+23=1615.
c) 711⋅34+711⋅14+411=711(34+14)+411=711+411=1711⋅34+711⋅14+411=711(34+14)+411=711+411=1.
d) (34+0,5+25%)⋅223=(34+12+14)⋅83=32⋅83=4(34+0,5+25%)⋅223=(34+12+14)⋅83=32⋅83=4.
a, 1- 1/2 + 1/3= 6-3+2/6 = 5/6; b, 2/5 +3/5 : 9/10 =2/5 +3/5.10/9= 2/5 + 2/3 = 16/15; c,7/11.3/4 + 7/11.1/4 +4/11 = 7/11( 3/4 + 1/4) + 4/11= 7/11 + 4/11= 11/11=1; d,(3/4+ 0.5+ 25%).2^2/3 = (3/4 +1/2 + 1/4).8/3= 3/2 . 8/3 = 4.
a) 1−12+13=6−3+26=561−12+13=6−3+26=56.
b) 25+35:910=25+35⋅109=25+23=161525+35:910=25+35⋅109=25+23=1615.
c) 711⋅34+711⋅14+411=711(34+14)+411=711+411=1711⋅34+711⋅14+411=711(34+14)+411=711+411=1.
d) (34+0,5+25%)⋅223=(34+12+14)⋅83=32⋅83=4(34+0,5+25%)⋅223=(34+12+14)⋅83=32⋅83=4.
a)=1-(1/2+1/3)=1-5/6=1/6 b)=(2/5+3/5):9/10=1:9/10=10/9 c)=7/11*(3/4+1/4)+4/11=7/11*1+4/11=7/11+4/11=11/11=1
a) 1−12+13=6−3+26=561−12+13=6−3+26=56.
b) 25+35:910=25+35⋅109=25+23=161525+35:910=25+35⋅109=25+23=1615.
c) 711⋅34+711⋅14+411=711(34+14)+411=711+411=1711⋅34+711⋅14+411=711(34+14)+411=711+411=1.
d) (34+0,5+25%)⋅223=(34+12+14)⋅83=32⋅83=4(34+0,5+25%)⋅223=(34+12+14)⋅83=32⋅83=4.
a)1-1/2+1/3
= 1/2 + 1/3
= 5/6
b)2/5+3/5+9/10
= 2/5 + 2/3
= 16/15
c)7/11.3/4+7/11.1/4+4/11
= 7/11 . ( 3/4 + 1/4 ) + 4/11
= 7/11 . 1 + 4/11
= 7/11 + 4/11
= 1
a)
\(1-\dfrac{1}{2}+\dfrac{1}{3}\\ =\dfrac{2}{2}-\dfrac{1}{2}+\dfrac{1}{3}\\ =\dfrac{1}{2}+\dfrac{1}{3}\\ =\dfrac{3}{6}+\dfrac{2}{6}\\ =\dfrac{5}{6}\)
b)
\(\dfrac{2}{5}+\dfrac{3}{5}:\dfrac{9}{10}\\
=\dfrac{2}{5}+\dfrac{3}{5}.\dfrac{10}{9}\\ =\dfrac{2}{5}+\dfrac{30}{45}\\ =\dfrac{2}{5}+\dfrac{2}{3}\\ =\dfrac{6}{15}+\dfrac{10}{15}\\ =\dfrac{16}{15}\)
c)
\(\dfrac{7}{11}.\dfrac{3}{4}+\dfrac{7}{11}.\dfrac{1}{4}+\dfrac{4}{11}\\ =\dfrac{7}{11}.\left(\dfrac{3}{4}+\dfrac{1}{4}\right)+\dfrac{4}{11}\\ =\dfrac{7}{11}.1+\dfrac{4}{11}\\ =\dfrac{7}{11}+\dfrac{4}{11}\\ =1\)
d)
\(\left(\dfrac{3}{4}+0,5+25\%\right).2\dfrac{2}{3}\\ =\left(\dfrac{3}{4}+\dfrac{1}{2}+\dfrac{1}{4}\right).\dfrac{8}{3}\\ =\left[\left(\dfrac{3}{4}+\dfrac{1}{4}\right)+\dfrac{1}{2}\right].\dfrac{8}{3}\\ =\left[1+\dfrac{1}{2}\right].\dfrac{8}{3}\\ =\dfrac{3}{2}.\dfrac{8}{3}\\ =4\)
a) 1-1/2+1/3
= 1/2 + 1/3
= 5/6
b)2/5+3/5:9/10
= 2/5 + 2/3
= 16/15
c)7/11.3/4+7/11.1/4+4/11
= 7/11 . ( 3/4 + 1/4 ) + 4/11
= 7/11 . 1 + 4/11
= 7/11 + 4/11
= 1
d)( 3/4+0,5+25%).2^2/3
= ( 3/4 + 1/2 + 1/4 ) . 8/3
= 3/2 . 8/3
= 4
