Question

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1/4 + 2/5 ; 5 + 4/7 - 5/7

Answer 1

\(\dfrac{1}{4}+\dfrac{2}{5}=\dfrac{5}{20}+\dfrac{8}{20}=\dfrac{5+8}{20}=\dfrac{13}{20}\)

\(5+\dfrac{4}{7}-\dfrac{5}{7}=\dfrac{35}{7}+\dfrac{4}{7}-\dfrac{5}{7}=\dfrac{35+4-5}{7}=\dfrac{34}{7}\)

Answer 2

\(\dfrac{1}{4}+\dfrac{2}{5}=\dfrac{5}{20}+\dfrac{8}{20}=\dfrac{13}{20}\)

\(5+\dfrac{4}{7}-\dfrac{5}{7}=\dfrac{35}{7}+\dfrac{4}{7}-\dfrac{5}{7}=\dfrac{34}{7}\)

Answer 3

\(\dfrac{1}{4}+\dfrac{2}{5}=\dfrac{5}{20}+\dfrac{8}{20}=\dfrac{13}{20}\)
\(5+\dfrac{4}{7}-\dfrac{5}{7}=\dfrac{35}{7}+\dfrac{4}{7}-\dfrac{5}{7}=\dfrac{35}{7}+\left(-\dfrac{1}{7}\right)=\dfrac{34}{7}\)