Question

 _3___ + __3____ + .... + ___3___    1×4       4×7             100×103

Answer 1

\(\dfrac{3}{1.4}+\dfrac{3}{4.7}+...+\dfrac{3}{100.103}\)
\(=1-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{7}+...+\dfrac{1}{100}-\dfrac{1}{103}\)
\(=1-\dfrac{1}{103}\)
\(=\dfrac{103}{103}-\dfrac{1}{103}\)
\(=\dfrac{102}{103}\)