Question

45.(7373/3030+7373/4242+7373/5656+7373/7272)

tính nhanh

Answer 1

\(45.\left(\frac{7373}{3030}+\frac{7373}{4242}+\frac{7373}{5656}+\frac{7373}{7272}\right)\)

\(=45.\left(\frac{101.73}{101.30}+\frac{101.73}{101.42}+\frac{101.73}{101.56}+\frac{101.73}{101.72}\right)\)

\(=45.\left(\frac{73}{30}+\frac{73}{42}+\frac{73}{56}+\frac{73}{72}\right)\)

\(=45.\left(\frac{73}{5.6}+\frac{73}{6.7}+\frac{73}{7.8}+\frac{73}{8.9}\right)\)

\(=45.73.\left(\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}\right)\)

\(=45.73.\left(\frac{1}{5}-\frac{1}{9}\right)\)

\(=45.73.\frac{4}{45}\)

\(=73.4\)

\(=292\)