等差级数 děng chā jí shù

DEFINITIONS

  1. arithmetic series (such as 2+4+6+8+...)

CHARACTERS

等 děng
HSK 2
rank, grade; wait; equal; 'etc.'
差 chā
HSK 3
to differ; different, wrong; nearly, almost; an officer
级 jí
HSK 3
level, rank, class; grade
数 shù
HSK 3
number; several, count; fate