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@Phúc

@Dekisugi Hidetoshi hong nhóm vào à?

chia hết mà

ihT chép trong chép

\(10\dfrac{2}{7}-6\dfrac{1}{3}+3\dfrac{5}{7}-4\dfrac{2}{3}+\dfrac{11}{37}\)

\(=\dfrac{72}{7}-\dfrac{19}{3}+\dfrac{26}{7}-\dfrac{14}{3}+\dfrac{11}{37}\)

\(=\left(\dfrac{72}{7}+\dfrac{26}{7}\right)-\left(\dfrac{19}{3}+\dfrac{14}{3}\right)-\dfrac{11}{37}\)

\(=14-11-\dfrac{11}{37}\)

\(=3-\dfrac{11}{37}\)

(\(=\dfrac{3}{1}-\dfrac{11}{37}\))

\(=\dfrac{111}{37}-\dfrac{11}{37}=\dfrac{100}{37}\)

35,8 x 5,3 + 358 x 0,12 - 0,65 x 258

Sửa hộ chj dòng đầu

Lớp 4 chưa học số âm nhé!

\(A=\dfrac{1}{2}+\dfrac{1}{6}+\dfrac{1}{12}+...+\dfrac{1}{380}\)

\(A=\dfrac{1}{1\times2}+\dfrac{1}{2\times3}+\dfrac{1}{3\times4}+...+\dfrac{1}{19\times20}\)

\(A=1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+...+\dfrac{1}{19}-\dfrac{1}{20}\)

\(A=1-\dfrac{1}{20}\)

\(A=\dfrac{19}{20}\)

\(\Rightarrow\) Vì \(\dfrac{19}{20}< 1\) nên

\(\Rightarrow A< 1\)

35,8×5,3+358×0,12-0,65×258

Sửa nhé