\(70.\left(\frac{252525}{565656}+\frac{252525}{727272}+\frac{252525}{909090}\right)\)
\(=70.\left(\frac{25}{56}+\frac{25}{72}+\frac{25}{90}\right)\)
\(=70.25.\left(\frac{1}{7.8}+\frac{1}{8.9}+\frac{1}{9.10}\right)\)
\(=1750.\left(\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}+\frac{1}{9}-\frac{1}{10}\right)\)
\(=1750.\left(\frac{1}{7}-\frac{1}{10}\right)\)
\(=1750.\frac{3}{70}\)
\(=75\)
Tính :
\(=70.\left(\frac{25}{56}+\frac{25}{72}+\frac{25}{90}\right)\)
=\(70.\frac{15}{14}\)
=75
knha