\(\dfrac{6}{7}km^2+\dfrac{9}{9}km^2+\dfrac{12}{14}km^2\)
Vận tốc nào dài hơn : \(\dfrac{2}{3}km/h\)và \(\dfrac{7}{9}km/h\)
Sao lại hỏi quãng đường em nhỉ? Vì đây là con số đi kèm đơn vị vận tốc mà???
tính thuận tiện:
\(\dfrac{4}{5}+\dfrac{2}{3}+\dfrac{1}{5}+\dfrac{1}{3}\) \(\dfrac{17}{12}+\dfrac{29}{7}-\dfrac{8}{7}+\dfrac{7}{12}\) \(\dfrac{9}{15}+\dfrac{16}{7}+\dfrac{2}{5}-\dfrac{1}{7}-\dfrac{2}{14}\)
\(\dfrac{2}{5}+\dfrac{6}{9}+\dfrac{7}{4}+\dfrac{3}{5}+\dfrac{1}{3}+\dfrac{1}{4}\)
mik sẽ chỉ tick 3 bn xong trước phải chi tiết rõ ràng
a: =4/5+1/5+2/3+1/3=1+1=2
b: =17/12+7/12+29/7-8/7=3+2=5
c: =3/5+2/5+16/7-1/7-1/7
=1+2=3
d: =2/5+3/5+2/3+1/3+7/4+1/4
=1+1+2
=4
\(\dfrac{4}{5}+\dfrac{2}{3}+\dfrac{1}{5}+\dfrac{1}{3}\)
\(=\left(\dfrac{4}{5}+\dfrac{1}{5}\right)+\left(\dfrac{2}{3}+\dfrac{1}{3}\right)\)
\(=\dfrac{5}{5}+\dfrac{3}{3}\)
\(=1+1\)
\(=2\)
============
\(\dfrac{17}{12}+\dfrac{29}{7}-\dfrac{8}{7}+\dfrac{7}{12}\)
\(=\left(\dfrac{17}{12}+\dfrac{7}{12}\right)+\left(\dfrac{29}{7}-\dfrac{8}{7}\right)\)
\(=\dfrac{24}{12}+\dfrac{21}{7}\)
\(=2+3\)
\(=5\)
====================
\(\dfrac{9}{15}+\dfrac{16}{7}+\dfrac{2}{5}-\dfrac{1}{7}-\dfrac{2}{14}\)
\(=\dfrac{9}{15}+\dfrac{16}{7}+\dfrac{6}{15}-\dfrac{1}{7}-\dfrac{1}{7}\)
\(=\left(\dfrac{9}{15}+\dfrac{6}{15}\right)+\left(\dfrac{16}{7}-\dfrac{1}{7}-\dfrac{1}{7}\right)\)
\(=\dfrac{15}{15}+\dfrac{14}{7}\)
\(=1+2\)
\(=3\)
===============
\(\dfrac{2}{5}+\dfrac{6}{9}+\dfrac{7}{4}+\dfrac{3}{5}+\dfrac{1}{3}+\dfrac{1}{4}\)
\(=\dfrac{2}{5}+\dfrac{2}{3}+\dfrac{7}{4}+\dfrac{3}{5}+\dfrac{1}{3}+\dfrac{1}{4}\)
\(=\left(\dfrac{2}{5}+\dfrac{3}{5}\right)+\left(\dfrac{2}{3}+\dfrac{1}{3}\right)+\left(\dfrac{7}{4}+\dfrac{1}{4}\right)\)
\(=\dfrac{5}{5}+\dfrac{3}{3}+\dfrac{8}{4}\)
\(=1+1+2\)
\(=4\)
VÒNG 2
Bài 1: Mèo con nhanh nhẹn
\(\dfrac{1}{2}\) + \(\dfrac{1}{12}\) | 2 + \(\dfrac{1}{6}\) | \(\dfrac{1}{20}\) | 1 - \(\dfrac{1}{9}\) | |
\(\dfrac{1}{15}\) + \(\dfrac{2}{15}\) | \(\dfrac{1}{2}\) + \(\dfrac{2}{3}\) | \(\dfrac{7}{12}\) | \(\dfrac{4}{12}\) | |
\(\dfrac{9}{14}\)+ \(\dfrac{1}{14}\) | 1 + \(\dfrac{1}{6}\) | \(\dfrac{1}{4}\) - \(\dfrac{1}{5}\) | \(\dfrac{1}{3}\) - \(\dfrac{2}{9}\) | |
\(\dfrac{3}{2}\) + \(\dfrac{2}{3}\) | \(\dfrac{1}{5}\) | 1 - \(\dfrac{8}{9}\) | ||
\(\dfrac{5}{7}\) | 1 - \(\dfrac{2}{3}\) | \(\dfrac{1}{3}\) + \(\dfrac{5}{9}\) |
tìm số tự nhin x bt
a.\(x-\)\(\dfrac{5}{14}=\dfrac{3}{7}-\dfrac{1}{14}\) b.\(\dfrac{2}{9}:x=\dfrac{1}{2}+\dfrac{2}{3}\) c.\(\dfrac{6}{32:x}=\dfrac{12}{16}\)
a: =>x-5/14=6/14-1/14=5/14
=>x=10/14=5/7
b; =>2/9:x=3/6+4/6=7/6
=>x=2/9:7/6=2/9*6/7=4/21
c: =>32:x=8
=>x=4
a
\(x-\dfrac{5}{14}=\dfrac{3}{7}-\dfrac{1}{14}\\ x-\dfrac{5}{14}-\dfrac{3}{7}+\dfrac{1}{14}=0\\ x+\dfrac{1}{14}-\dfrac{5}{14}-\dfrac{6}{14}=0\\ x+\dfrac{1-5-6}{14}=0\\ x-\dfrac{5}{7}=0\\ x=0+\dfrac{5}{7}\\ x=\dfrac{5}{7}\)
b
\(\dfrac{2}{9}:x=\dfrac{1}{2}+\dfrac{2}{3}\\ \dfrac{2}{9}:x=\dfrac{3}{6}+\dfrac{4}{6}\\ \dfrac{2}{9}:x=\dfrac{3+4}{6}=\dfrac{7}{6}\\ x=\dfrac{2}{9}:\dfrac{7}{6}\\ x=\dfrac{2}{9}\times\dfrac{6}{7}=\dfrac{2.3.2}{3.3.7}=\dfrac{4}{21}\)
c
\(\dfrac{6}{32:x}=\dfrac{12}{16}\\ 32:x=6:\dfrac{12}{16}\\ 32:x=6\times\dfrac{16}{12}\\ 32:x=\dfrac{3\times2\times4\times4}{3\times4}\\ 32:x=8\\ x=\dfrac{32}{8}\\ x=4\)
`@` `\text {Answer}`
`\downarrow`
`a,`
`x - 5/14 = 3/7 - 1/14`
`x - 5/14 = 5/14`
`=> x = 5/14 + 5/14`
`=> x = 5/7`
Vậy, `x = 5/7`
`b,`
`2/9 \div x = 1/2 + 2/3`
`2/9 \div x = 7/6`
`x = 2/9 \div 7/6`
`x = 4/21`
Vậy, `x = 4/21`
`c,`
\(\dfrac{6}{32\div x}=\dfrac{12}{16}\)
`6/(32 \div x) = 3/4`
`32 \div x = 6 \div 3/4`
`32 \div x = 8`
` x = 32 \div 8`
`x = 4`
Vậy, `x = 4`
Viết số thập phân thích hợp vào chỗ chấm
\(\dfrac{3}{5}\) giờ =....giờ
\(\dfrac{5}{4}\) m =.....m
\(\dfrac{5}{8}\) giờ =....giờ
\(\dfrac{9}{5}\) km =.....km
\(\dfrac{3}{5}\) phút =.....phút
\(\dfrac{7}{8}\) kg =.....kg
`3/5` giờ `=0,6` giờ
`5/4m=1,25m`
`5/8` giờ `=0,625` giờ
`9/5km=1,8km`
`3/5` phút `=0,6` giờ
`7/8kg=0,875kg`
\(\dfrac{3}{5}\) giờ = 0,6 giờ
\(\dfrac{5}{4}m=1,25m\)
\(\dfrac{5}{8}\) giờ = 0,625 giờ
\(\dfrac{9}{5}km=1,8km\)
\(\dfrac{3}{5}\) phút = 0,6 phút
\(\dfrac{7}{8}kg=0,875kg\)
Thực hiện phép tính (tính hợp lý nếu có thể):
a) \(\dfrac{5}{9}.\dfrac{7}{13}+\dfrac{5}{9}.\dfrac{8}{13}-\dfrac{5}{13}.\dfrac{2}{9}\) b) \(12\dfrac{5}{14}-\left(3\dfrac{5}{7}+5\dfrac{5}{14}\right)\)
c)\(\dfrac{-2}{5}+\dfrac{7}{11}+\dfrac{-11}{10}+\dfrac{7}{-11}\) d) \(\dfrac{1}{2}+\dfrac{-2}{3}+\dfrac{1}{6}+\dfrac{-2}{5}\)
b: =12+5/14-3-5/7-5-5/14
=4-5/7
=28/7-5/7=23/7
c: =(-2/5-11/10)+(7/11-7/11)
=-4/10-11/10=-15/10=-3/2
\(a,\dfrac{5}{9}\cdot\dfrac{7}{13}+\dfrac{5}{9}\cdot\dfrac{8}{13}-\dfrac{5}{13}\cdot\dfrac{2}{9}\)
\(=\dfrac{5}{9}\cdot\dfrac{7}{13}+\dfrac{5}{9}\cdot\dfrac{8}{13}-\dfrac{2}{13}\cdot\dfrac{5}{9}\)
\(=\dfrac{5}{9}\cdot\left(\dfrac{7}{13}+\dfrac{8}{13}-\dfrac{2}{13}\right)\)
\(=\dfrac{5}{9}\cdot\dfrac{14}{13}\)
\(=\dfrac{70}{117}\)
\(d,\dfrac{1}{2}+\dfrac{-2}{3}+\dfrac{1}{6}+\dfrac{-2}{5}\)
\(=\left(\dfrac{1}{2}+\dfrac{-2}{3}+\dfrac{1}{6}\right)+\dfrac{-2}{5}\)
\(=0+\dfrac{-2}{5}\)
\(=\dfrac{-2}{5}\)
Tính:
a) \(\dfrac{5}{6}-\dfrac{4}{6}\) b) \(\dfrac{7}{12}-\dfrac{6}{12}\) c) \(\dfrac{7}{9}-\dfrac{2}{9}\) d) \(\dfrac{16}{5}-\dfrac{9}{5}\)
a: \(\dfrac{5}{6}-\dfrac{4}{6}=\dfrac{5-4}{6}=\dfrac{1}{6}\)
b: \(\dfrac{7}{12}-\dfrac{6}{12}=\dfrac{7-6}{12}=\dfrac{1}{12}\)
c: \(\dfrac{7}{9}-\dfrac{2}{9}=\dfrac{7-2}{9}=\dfrac{5}{9}\)
d: \(\dfrac{16}{5}-\dfrac{9}{5}=\dfrac{16-9}{5}=\dfrac{7}{5}\)
a) Thời gian nào dài hơn : \(\dfrac{2}{3}\) giờ hay \(\dfrac{3}{4}\) giờ
b) Đoạn thẳng nào ngắn hơn : \(\dfrac{7}{10}m\) hay \(\dfrac{3}{4}m\)
c) Khối lượng nào lớn hơn : \(\dfrac{7}{8}kg\) hay \(\dfrac{9}{10}kg\)
d) Vận tốc nào nhỏ hơn \(\dfrac{5}{6}km\)/h hay \(\dfrac{7}{9}km\)/h
a)\(\dfrac{2}{3}giờ< \dfrac{3}{4}giờ\)
b)\(\dfrac{7}{10}m< \dfrac{3}{4}m\)
c)\(\dfrac{7}{8}kg< \dfrac{9}{10}kg\)
d)\(\dfrac{5}{6}\)km/h >\(\dfrac{7}{9}\)km/h
a) h <
h
b) m <
m
c) kg <
kg
d) km/h >
km/h.
(\(\dfrac{7}{2^9}\)-\(\dfrac{14}{2^{11}}\)+\(\dfrac{21}{768}\))2 :(\(\dfrac{5}{2^9}\)-\(\dfrac{20}{2^{12}}\)+\(\dfrac{25}{1280}\))2
hộ tui các ace bốn phương ơi