算术平均数

• ⺮(bamboo (radical))RADICAL
• 具(tool; implement)PHONO-SEMANTIC

Ancient calculation used bamboo sticks as a tool to count numbers.

• 干(trunk; stem (horizontal representation))ASSOCIATIVE
• 丷(two diverging strokes; balance)ASSOCIATIVE

An upright tree trunk with two branches spreading equally on both sides symbolizes flatness and fairness.

• 娄(many times; piled up)PHONO-SEMANTIC
• 攵(tap; hand motion)RADICAL

Counting numbers is using your hand to tap repeatedly many times in order to calculate.