Maths.........very easy!

Maximum error
=1/2*difference between the finest markings on the measurement tools
For example,
the finest marking of a ruler is 1mm
so the maximum error of the ruler
=1/2*1mm
=0.5mm

Relative error
=maximum error/measures value
We can use another formula to express relative error too!
Relative error
=absolute error/actual value

I am very sorry that I don't know how to tipe in chinese, but I hope this can help you.

maximum absolute error　＝最大絕對誤差
relative error　＝相對誤差

maximum absolute error 是最大的誤差..
relative error我不懂啦