1. \(\frac{5}{10}=\frac{1}{2};\frac{3}{15}=\frac{1}{5};\frac{40}{70}=\frac{4}{7};\frac{24}{36}=\frac{2}{3};\frac{70}{42}=\frac{5}{3}\)
2. a) MSC: 12
Ta có: \(\frac{5}{3}=\frac{5.4}{3.4}=\frac{20}{12};\frac{1}{4}=\frac{1.3}{4.3}=\frac{3}{12}\)
b) MSC: 24
Ta có: \(\frac{3}{8}=\frac{3.3}{8.3}=\frac{9}{24}\) và \(\frac{7}{24}\)
c) MSC: 30
Ta có: \(\frac{1}{2}=\frac{1.15}{2.15}=\frac{15}{30}\)
\(\frac{2}{3}=\frac{2.10}{3.10}=\frac{20}{30}\)
\(\frac{3}{5}=\frac{3.6}{5.6}=\frac{18}{30}\)
1.
\(\frac{5}{10}\)= \(\frac{5:5}{10:5}\)= \(\frac{1}{2}\) \(\frac{3}{15}\)= \(\frac{3:3}{15:3}\)= \(\frac{1}{5}\)
\(\frac{40}{70}\)= \(\frac{40:10}{70:10}\)= \(\frac{4}{7}\) \(\frac{24}{36}\)= \(\frac{24:12}{36:12}\)= \(\frac{2}{3}\)
\(\frac{70}{42}\)= \(\frac{70:14}{42:14}\)= \(\frac{5}{3}\)
1.\(\frac{5}{10}\)= \(\frac{5:5}{10:5}\)=\(\frac{1}{2}\); \(\frac{3}{15}\)= \(\frac{3:3}{15:3}\)=\(\frac{1}{5}\); \(\frac{40}{70}\)=\(\frac{40:10}{70:10}\)=\(\frac{4}{7}\); \(\frac{24}{36}\)=\(\frac{24:12}{36:12}\)=\(\frac{2}{3}\); \(\frac{70}{42}\)=\(\frac{70:14}{42:14}\)=\(\frac{5}{3}\)
2. \(\frac{5}{3}\)và \(\frac{1}{4}\)
MC( 3 , 4) = 12
12:3 = 4
12:4= 3
Quy đồng : \(\frac{5}{3}\)= \(\frac{5x4}{3x4}\)= \(\frac{20}{12}\); \(\frac{1}{4}\)= \(\frac{1x3}{4x3}\)= \(\frac{3}{12}\)
\(\frac{3}{8}\) và \(\frac{7}{24}\)
MC( 8 , 24 ) = 24
24: 8 = 3
24:24 =1
Quy đồng:\(\frac{3}{8}\)= \(\frac{3x3}{8x3}\)=\(\frac{9}{24}\); \(\frac{7}{24}\)=\(\frac{7x1}{24x1}\)= \(\frac{7}{24}\)
\(\frac{1}{2}\),\(\frac{2}{3}\)và \(\frac{3}{5}\)
MC( 2 , 3, 5) =30
30:2= 15
30: 3= 10
30: 5 =6
Quy đồng;\(\frac{1}{2}\)=\(\frac{1x15}{2x15}\)=\(\frac{15}{30}\); \(\frac{2}{3}\)=\(\frac{2x10}{3x10}\)=\(\frac{20}{30}\); \(\frac{3}{5}\)=\(\frac{3x6}{5x6}\)=\(\frac{18}{30}\)
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