1/1×4+1/4×7+1/7×10+…+1/13×16简便运算

问题描述:

1/1×4+1/4×7+1/7×10+…+1/13×16简便运算

1/1×4+1/4×7+1/7×10+…+1/13×16
=1/3(1-1/4)+1/3(1/4-1/7)+1/3(1/7-1/10)...+1/3(1/13-1/16)
=1/3(1-1/16)
=5/16