Commutativity and associativity might sound the same, and indeed most commutative operations are also associative. But there are a few math operations that are only one or the other. Matrix multiplication, for example, is associative but not commutative Matrix multiplication - Wikipedia en.wikipedia.org/wiki/Matrix_multiplication#Non-commutativity . And surprisingly, floating point arithmetic — i.e. any math operator in JavaScript — is commutative but not associative Associative property - Wikipedia en.wikipedia.org/wiki/Associative_property#Nonassociativity_of_floating_point_calculation ! ↩
（二）货物共同海损牺牲的金额，货物灭失的，按照货物在装船时的价值加保险费加运费，减除由于牺牲无需支付的运费计算。货物损坏，在就损坏程度达成协议前售出的，按照货物在装船时的价值加保险费加运费，与出售货物净得的差额计算。
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