The assignment of a symbolic representation to a specific numerosity is a fundamental requirement for humans solving complex mathematical calculations used in diverse applications such as algebra, accounting, physics, and everyday commerce. Here we show that honeybees are able to learn to match a sign to a numerosity, or a numerosity to a sign and subsequently transfer this knowledge to novel numerosity stimuli changed in colour properties, shape, and configuration. While honeybees learnt the associations between two quantities (two; three) and two signs (N-shape; inverted T-shape), they failed at reversing their specific task of sign-to-numerosity-matching to numerosity-to-sign-matching and vice-versa (i.e. a honeybee that learnt to match a sign to a number of elements was not able to invert this learning to match the numerosity of elements to a sign). Thus, while bees could learn the association between a symbol and numerosity, it was linked to the specific task and bees could not spontaneously extrapolate the association to a novel, reversed task. Our study therefore reveals that the basic requirement for numerical symbolic representation can be fulfilled by an insect brain suggesting that the absence of its spontaneous emergence in animals is not due to cognitive limitation.