Introducing new concepts to learners in an order of increasing complexity appears to be beneficial for learning, but typically introduction of concepts does not always adhere to this principle. We examined whether introducing new algebra concepts in a contrasted manner or in an order of increasing complexity instead of a different more typical order influences learning and retention. A total of 138 sixth graders were introduced to algebraic expression simplification. In algebra, addition of terms is usually introduced before multiplication of terms. However, the concept of addition appears to be structurally more complex than the concept of multiplication. Two experimental conditions in which algebraic multiplication was either introduced first, or both concepts simultaneously, caused substantially stronger learning gains and better retention compared with a third condition with the more typical order. Contrasted presentation of both concepts performed best, with strongest and most stable learning gains. Presenting multiplication first led to comparable gains on addition problems, but to lower achievement on multiplication problems in the longer delay. These findings suggest a rethinking of introduction orders in algebra and beyond.