Question 142
Find the sum of
$$
\frac{1}{2 \times 5}+\frac{1}{5 \times 8}+\frac{1}{8 \times 11}+\cdots+\frac{1}{2009 \times 2012}
$$
$$
\frac{1}{2 \times 5}+\frac{1}{5 \times 8}+\frac{1}{8 \times 11}+\cdots+\frac{1}{2009 \times 2012}
$$
MathNet 2026 — Part 07 Question 142
Math Olympiad Vault · MathNet 2026 — Part 07