Lake Crystal has twenty percent fewer frogs than Lassie Lake. If Lassie Lake has forty-five frogs, how many frogs are there in total in the two lakes?
Let's be accurate as possible and think first.
81
Lake Crystal has twenty percent fewer frogs than Lassie Lake, a total of 20 / 100 * 45 = 9 frogs.

The total number of frogs in Lake Crystal is 45 - 9 = 36.

Together, the two lakes have 36 + 45 = 81 frogs.

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Final answer: 81