HKIMO 2017 Grade 6 National Final (Heat) Set 04 Question 7

Find $\frac1{1\times2\times3}+\frac1{2\times3\times4}+\cdots+\frac1{7\times8\times9}+\frac1{8\times9\times10}$.

Source glossary (English–Vietnamese): Value: giá trị.