Question

bài 3: tính bằng cách thuận tiện: a) 17/12 + 29/7 - 8/7 + 7/12       b) 2/5 + 6/9 + 7/4 + 3/5 + 1/4 + 1/3 

Answer 1

a: \(\dfrac{17}{12}+\dfrac{29}{7}-\dfrac{8}{7}+\dfrac{7}{12}\)

\(=\left(\dfrac{17}{12}+\dfrac{7}{12}\right)+\left(\dfrac{29}{7}-\dfrac{8}{7}\right)\)

\(=\dfrac{24}{12}+\dfrac{21}{7}=2+3=5\)

b: \(\dfrac{2}{5}+\dfrac{6}{9}+\dfrac{7}{4}+\dfrac{3}{5}+\dfrac{1}{4}+\dfrac{1}{3}\)

 

\(=\left(\dfrac{2}{5}+\dfrac{3}{5}\right)+\left(\dfrac{6}{9}+\dfrac{1}{3}\right)+\left(\dfrac{1}{4}+\dfrac{7}{4}\right)\)

\(=1+1+2=4\)

Answer 2

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