Tính bằng cách thuận tiện nhất:
a) 96 + 78 + 4
67 + 21 + 79
408 + 85 + 92
b) 789 + 285 + 15
448 + 594 + 52
677 + 969 + 123
Tìm y,biết:
a,\(y-\frac{1}{3}=\frac{10}{21}\div\frac{15}{28}\)
b,\(\frac{2}{7}\div y=\frac{10}{21}\times\frac{9}{14}\)
tính bằng cách thuận tiện nhất
a,\(\frac{6}{7}\cdot\frac{16}{15}\cdot\frac{7}{6}\cdot\frac{21}{32}\)b, \(\frac{21}{17}\cdot\frac{13}{14}\cdot56\cdot\frac{3}{42}\) c,\(\frac{7}{4}\cdot\frac{11}{21}+\frac{11}{21}\cdot\frac{5}{4}\) d,\(\frac{23}{14}\cdot\frac{6}{14}-\frac{9}{14}\cdot\frac{6}{13}\)
tính nhanh \(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+\frac{1}{28}+\frac{1}{36}+\frac{1}{45}+\frac{1}{55}\)
Tính nhanh : \(\frac{4}{3}+\frac{7}{6}+\frac{11}{10}+\frac{16}{15}+\frac{22}{21}+\frac{29}{28}+\frac{37}{36}+\frac{46}{45}\)
\(\frac{1}{3}\)=\(\frac{5}{15}\)=\(\frac{ }{21}\)
Tìm x \(\left(1+\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+\frac{1}{15}+\frac{1}{21}\right)\times X=\frac{8}{9}\)
Viết tiếp vào chỗ chấm:
a) \(\frac{24}{60}=\frac{...}{15}=\frac{...}{5}=\frac{8}{...}\)
b) \(\frac{42}{54}=\frac{7}{...}=\frac{...}{18}=\frac{21}{...}\)
Tính:
a, \(\frac{2}{3}+\frac{5}{4}\)
b, \(\frac{15}{25}+\frac{6}{21}\)
c, \(\frac{4}{3}-\frac{11}{15}\)
d, \(\frac{12}{10}-\frac{2}{5}\)
So sánh phân số ( ko quy đồng )\(\frac{47}{15}và\frac{65}{21}\)